The only problem I have with this statement is that, if we are going by the idea that Stan wants out of St Louis and into LA, the NFL is seriously interfering with his ability to conduct his business as he sees fit. I get the franchise stuff and anti-trust status and all that but I'm going to guess that if it were to go to court, the Supreme's ruling that the NFL is made up of 32 independent businesses will likely come into the equation.
A half funded stadium where Stan is only able to recoup his share of NFL allotted revenues and nothing else from his essentially $450 million investment, would be potentially difficult to defend. It's just my guess on how it would go if he really wanted to push it.
He is offering to build without public money. I think that frees him up from a lot of potential restrictions. I think it also would be viewed positively by members of the legislature that are grumbling about the idea of public monies being used to build stadiums. If anything, this kind of a project might save the NFL's anti-trust status as it is purely business without the taxpayers having to foot the bill for a potentially vagabond team.
All that being said, the best and only way for St Louis to keep the Rams is still to get a workable plan locked down with everything in place ASAP. If they do that, they would be applying the most pressure on everyone involved to vote against Stan and at minimum force a long drawn out process that would most negatively affect Stan.