The east coast has entire Ivy League and yet no Silicon Valley. Also, how do you explain Seattle?
Seattle at one point had Microsoft as the hub, Amazon came on the scenes in 2000s - once they both reached critical mass, there was practically no stopping the growth because engineers had an alternative. Eventually we had FB/Twitter/Snap et al starting offices here and having massive presences which led to present day. If only the weather wasn't what it is, I think we would have reached this ~20 yrs ago.
I don't know if it is going to be Austin / Boulder - but once any of those cities build two equally good employment opportunities, it is going to be a real contender. This is what makes TSLA / Oracle move significant: till now what were outposts are becoming real hubs.