When it came down to a decision on Nationals Stadium, despite strong opposition, I think the deciding factor was that we would lose the team to another city if there was not going to be a stadium, and the Council did not want to be responsible for maintaining DC as a Non Major League City. That's not the case with the Redskins. DC is an NFL city (despite where the Redskins play) and the Redskins aren't leaving the area if the city doesn't build them a stadium.
nother argument is that baseball generates far more revenue with 80+ games, than football, with a tenth that many.
I think for football, you can ask what does Loudon, PG, or whereever have to gain. If every jurisdiction answers the question honestly, I think the redskins end up without a new stadium. I think it applies pretty universally to pro stadiums- Detroit just paid $850 million and the justification was to revitalize - it's still a new and shiny building, but there is no way it will ever drive to traffic to justify the price and it's already having trouble selling tickets
To the extent that the nationals are an exception, I think it's more because it required the city to clear the area for development than the stadium itself.
