What’s Behind All the Domed NFL Stadiums Being Built?

ANDREW ZIMBALIST: Which isn’t to say the trade-offs disappear. You’re still cut off from actual weather. But the sealed-in-concrete-bunker feeling that drove the original critique isn’t what these buildings do anymore.

WSJ:What are the basic categories of stadium enclosure that a fan should understand?

LONG: There are essentially four. Open-air is the traditional format, which accounts for half the league today, dropping to about a third by 2030. Then there’s “fixed-roof,” which includes everything from the old concrete domes like the Caesars Superdome in New Orleans to the new ETFE structures like SoFi in Los Angeles. “Partial-roofs” cover mainly the seating bowl, but leaves the field open, protecting 60% to 70% of fans while maintaining some connection to the elements.

That’s what Buffalo is building for the Bills. And then there are “retractables,” though virtually no one is building those anymore. They’re expensive, mechanically complicated and almost always closed anyway. The real action is in newer fixed-roof ETFE designs.

WSJ: Why now? What’s driving this wave of construction?

ZIMBALIST: A few things are converging at once. Start with the economics of the NFL stadium itself: A team plays nine or so home games a year—that’s 10 days of use out of 365. If you’re building one of these facilities, you need it to earn money at least some of the other 355 days. An enclosed venue gives you the ability to host major concerts, conventions and other events that simply aren’t practical in an open-air stadium. Once you’ve decided to enclose it, you’ve changed the whole calculus of the building.

LONG:The Super Bowl calculus is related. Over the last 15 years, only three Super Bowls have been played in open-air venues. The NFL’s hosting rules require a roofing enclosure if the average game-day temperature falls below 50 degrees—which rules out most of the country for most of the winter. If your city wants one, you almost certainly need a roof.

ZIMBALIST: And there’s another dimension that doesn’t get enough attention: television. The overwhelming majority of NFL revenue comes from broadcast contracts. If you want to maximize those deals, you want to offer networks and streaming services certainty. You don’t want them reserving a Monday-night slot and having the game delayed by weather, or worse, called off. The enclosed venue is fundamentally a product of the television economy.

The cost context is worth spelling out. A new stadium now runs roughly $2 to $3 billion as a baseline. An ETFE roof adds $200 to $500 million depending on complexity.

Who pays?

WSJ:Who actually pays for these things? The public share seems to be shrinking—is that really happening?

LONG:It’s what I’d call the declining public-share paradox. For NFL stadiums overall, the average public subsidy runs around 60%. For the newer builds—post-2009, most of which have roofs—it’s closer to 40%, or 48% if you strip out SoFi, which was fully privately financed and skews the numbers. So, it looks like we’re paying less of the tab, but in absolute dollars, taxpayers are paying far more than ever, because the stadiums cost so much more. Forty percent of $3 billion is $1.2 billion. Sixty percent of $300 million—what Baltimore’s MLB stadium, Camden Yards, cost in 1992—was $180 million.

ZIMBALIST: And the published percentages rarely capture the full picture. When cities reduce direct cash contributions, owners typically ask for something else, like favorable land deals at below-market prices, tax abatements, new highway ramps and infrastructure built at public expense, sanitation and security services. Sometimes a surrounding mixed-use area is designated as a special tax zone, so that future tax revenues from the development are pledged to pay off the stadium bonds—meaning the city is effectively pre-spending decades of future tax income.

The numbers that politicians and owners put in front of voters are almost never comprehensive. A stadium that looks like a 50-50 deal may really be a 70-30 deal once you factor in the land and the off-balance-sheet subsidies.

WSJ: Does any of this actually benefit the city economically? Or just the owner?

ZIMBALIST:The research is pretty consistent: Stadiums don’t generate meaningful economic development. When a family spends $300 at a game, that’s $300 they don’t spend at a local restaurant or bowling alley; there’s no new economic activity, just what we economists call “substitution.” Much of the money spent inside the stadium flows to owners and players whose primary residences are elsewhere and who save at high rates, and thereby leaks out of the city’s economy.

And if the city’s bond debt service exceeds the revenue the stadium generates, you have a continuing fiscal hole that forces cuts to services, or tax increases.

WSJ: There’s a view that weather is a player on the field—that a snowy game in December in Buffalo is part of what football is. What do we lose when we take weather out of the equation?

LONG:It’s a genuine loss, and I don’t want to minimize it. The weather has always been part of the drama—the 1967 Ice Bowl, the 2002 Tuck Rule game, any number of moments where the conditions became characters in the story. When you enclose the stadium, you’re removing a variable that has shaped the game for a century. Whether that matters to you probably depends on your relationship to the sport. There are fans for whom cold-weather football is almost a spiritual experience. And there are fans—and owners, and broadcasters—for whom it’s an obstacle to a reliable, comfortable, marketable product.

There’s also the question of competitive equity. A team that plays in an enclosed stadium never has to worry about a snowstorm neutralizing its passing game. A dome team that makes the playoffs and has to play outdoors is suddenly disadvantaged. Whether you think that’s a problem depends on whether you believe weather conditions are a feature of the sport or merely a bug.

The impact on fans

WSJ: Is the fan experience better, or just more expensive?

LONG:Both. The share of seating classified as luxury—suites, club seats, loge sections—has risen to 12% to 15% across NFL venues since the pre-1992 era. The enclosed venue makes premium seating easier to sell, because corporate clients are buying guaranteed comfort and weather certainty alongside the game. But when you raise your capital basis by $300 million for a roof, you have to charge more for everything to service that debt. The roof isn’t free to fans.

WSJ: Will open-air stadiums survive?

LONG: Yes, some will. Lambeau Field [in Green Bay, Wis.] isn’t going under a roof. Neither is Highmark Stadium in Buffalo, N.Y. There will always be franchises in markets where the outdoor tradition is too embedded in the team’s identity to abandon, or where the economics don’t justify the cost of an enclosure. But the trend line is clear. By 2030 we’ll be down to about 10 open-air venues in the NFL. Whether that number holds or keeps falling probably depends on whether climate change eventually makes outdoor football in, say, Miami or Phoenix untenable for different reasons than it does in Buffalo.

ZIMBALIST: I’ll say this: I’d personally rather see a city invest equivalent public dollars in a museum or a concert hall—institutions that strike me as more genuinely culturally enriching. But I go to games, and I see what they generate: a shared experience, a common identity, a sense of community in a country that has fewer and fewer of those things. Whatever these domed stadiums are, they’re not nothing. The question is whether they’re worth what we’re paying for them.

Write to reports@wsj.com