Basically, if we could at least get the ease of raising seed funding in Atlanta at parity with the ease of raising 1st round for a startup with revenues, it would be a significant win for us.
I do agree with you that if there were more VCs funding at the $1M level in Atlanta, we could keep all the Shotput applicants here and maybe a bunch of startups would move from across the country to Atlanta. But since politicians are unlikely to be as enlightened as making the $1B investment you mention in your essay would require, we'll have to attract private investors. If 1 of those 4 startups has a big successful exit, we'll probably get 1 more large fund to come to Atlanta.
This assumption is off by an order of magnitude. YC funded 61 startups in Boston. Only 3 are still there, and 1 of those is talking about moving to SV. So the assumption should be more like 2-3%.
So unless they restrict applications, there will end up being little local component, just as with every previous seed firm. Techstars intended to be the YC of Boulder. But IIRC only 4 of the 20 startups they've funded so far have been from Colorado. As far as I know, the same thing has happened to everyone after them as well.
The seed funding business isn't regional. People would like to believe it is, because it's 20x cheaper to run a YC than to do what you'd actually have to do to make startups stick to a particular city. But it isn't.