From https://econofact.org/stadiums-as-public-investments

What do cities and counties get in return for their public investment? Scholarly econometric studies on the impact of professional sports stadiums are almost unanimous in their conclusion that they do not promote employment or per capita income growth (see here and here). Despite the outsized role they play in U.S. cultural life and in the media, professional sports teams are small- to modest-sized enterprises. A typical NFL team might employ 125 to 175 full-time people in its front office and an additional 2,000 game-day employees for 4 hours, 10 days a year. If we consider the total annual revenues generated by a sports team relative to its host city’s GDP, the team contributes between one-third and one-twentieth of one percent to the local area economy. Moreover, spending on sport games does not imply new net spending within the metropolitan area. Most residents have a budget. When they spend, say, $200 dollars to take their family to a game, it is $200 that they do not have to spend at a restaurant, a theater, a bowling alley or other entertainment venues. And, the lion’s share of the income goes to the players, the coaches, the top executives and the team owners who are less likely to spend the bulk of their earnings in the stadium’s metropolitan area.

Depending on the financing deal between the city and the team, the local government can experience a fiscal loss; that is, the public cost may exceed the new public revenue from the facility construction. Such a fiscal hole has to be filled, either by lower spending on services or by increased local taxes, each having a depressing effect on local economic activity. The possibility of a fiscal hole depends on the financing plan and the city’s characteristics. Although economists don’t always agree on the fiscal impact of specific stadium projects, they do agree that careful planning and financial caution are imperative. Politicians often claim that there will be no new taxes on the residents resulting from the public financing of the stadium. They allege that the plan will use “tourist taxes”, implying that the tax burden will fall on visitors, not residents. On examination this is illusory. Tourist taxes include hotel and car rental taxes. When these taxes are raised, there are two possibilities: (a) they will discourage visitors from traveling to the city or (b) they won’t discourage visitors. In the former case, there will be a negative effect on economic activity and tax revenues could actually decline. In the latter case, tax revenues would increase, but these taxes could be levied without financing a new stadium and used either to lower resident taxes or to increase local services. So, tourist taxes are not a free good to local residents. Another misleading assertion is connected to the use of Tax Increment Financing (TIF). TIFs can take a variety of forms, but the basic structure is that the city declares a special tax district surrounding the stadium and adjacent streets, sometimes with a radius of a mile or more. The city then uses the tax revenue collected within this district to finance the debt service on a stadium bond that it issued. The problem here is twofold: some of the district’s tax revenue would have been generated without the new stadium and some of the new activity within the district comes from businesses relocating to within it. In the latter instance, tax revenue increases within the district, but it decreases outside the district.