I think the Danica effect have been underestimated in it's heyday, I agree the lust have gone off now that she is not really performing in NASCAR, I do not think Formula 1 would suddenly be the number one choice for the US TV viewers, but there were 400K paying spectators this weekend, there must have been an ok number of people watching, a good number of which had no idea Rossi existed before the race, who have now heard him mentioned as a F1 driver, and they saw him win the 500.
The sport could do a lot worse than putting him in a F1 seat next season, there would be some traction not currently there.
The Danica Value, whether Indycar or NASCAR, is mostly tied to Danica. It doesn't really increase funding for anyone else.
And those 400k were already watching the 500 without Rossi. Likewise the 5mil+ they'll have had on TV. Even if you could convert all of them to F1 it'd be a minor uptick. And the main beneficiary would be Rossi and the team he drives for. He might, though highly unlikely, be able to bring some money to a front running team. Or Honda might shoehorn him into McLaren or a customer Honda team or something.
But F1 won't crack America that way. It's a round peg in a square hole, or whatever.