If this falls through, there will be an enormous amount of celebration from the damn fools, then they will pay tens of millions of dollars to remove the old RFK stadium, and then the land will basically sit vacant as they argue about it for the next 10 years.
The one thing that has to happen is they have to pull the old stadium down. It's costing money for some degree of upkeep, it's falling down anyway, and it's just an empty eyesore.
They're going to get the bill to pull it down, balk at it, realize there is no offsetting increase in revenue, and then do be stuck as Harris builds a new stadium in Maryland.
I'm really hoping Harris can help save DC from itself. I'm actually somewhat dubious he will be successful. I might be cynical, but I still think there's a 50% chance the stadium ends up exactly where it currently is because the DC government does not have a track record of doing anything productive for the football team. I keep going back to the fact after 3 SBs and 4 SB appearances, DC failed to be able to work something out with JKK. Literally anything is believable.
I do think that would be a HUGE black eye for the city though, because it is in no small part due to the lobbying the Harris group did the land is even in DC's control. It's his group which lobbied and got the bill through the Senate to even return the land to DC. It would be an enormous middle finger to Harris, and honestly the Senators who voted for the bill, to then say "thanks, but we're not going to use it for the purpose (even if it was subtly stated) you intended it to be used for.
But as I said, they DC Government doesn't have a good track record for working with this team. Ironically, they've been better with Ted and the Nats than with the football team, and that track record goes back 50 years. And they would have lost the Caps/Wiz if Louis from VA hadn't nuked the "Glenn Dome" in Virginia.