When I was coming up there was a huge brain drain going on from the midwest. A lot of those people ended up in Seattle, because of Seattle, NYC and SF, Seattle seems the smallest culture change (that is of course debatable, especially with the Seattle Freeze). Since then Chicago has become eminent in fintech, so I expect some people end up there, but that's not everybody's speed either.
Saint Louis is also pretty centrally located from an Internet infrastructure standpoint and as far as I'm aware they've not amounted to much of anything from an IT standpoint since ftp.wustl.edu. It looks like Boeing, Square, and a bunch of banks have offices there.
That may have to do with secondary issues like the quality of education in Missouri. Undergrads might not give a damn but founders and VCs might care quite a bit.