Yes, I did say you would probably still move (and still
want to move). But not necessarily to SV.
If there are 'only' 5-6 startup hubs today, not too long ago there was only one. Since the other 4-5 hubs managed to grow in spite of SV's existence (and dominance), I do expect this number to increase further, by one order of magnitude at least.
I don't think the star-system is necessarily a relevant analogy because it is focusing on individuals, who as actors, actually have quite a few more options than just Hollywood. Rather, what would happen if 50% of the next generation of movie producers and production companies were from St. Louis (or Bollywood)? Or, for a different scenario, 50% of the next generation of SFX and post-production companies? Do they all have to move to Hollywood? Can some of them move back? For some types of companies, It's actually demonstrable that they don't all make the move, and a rash of soundstages and post-production facilities are sprouting up in secondary hubs across the US because Hollywood is too expensive and crowded.
Your empirical argument is well taken. By no means was I arguing that SV would become irrelevant to the current industry because of growth per-se, but you're assuming that startups are (and will remain) an 'industry', and second, that they will remain the same industry.
Personally, I anticipate quite a bit more disruption and creative destruction than that. The US rust-belt is testimony that further growth in an industry can under the right circumstances pass existing hubs by, eventually making them irrelevant because the industry itself has changed in fundamental ways. It is also possible that 'startups' might get distributed into the broader economic fabric as thoroughly as 'web design' or 'desktop publishing'. This may actually be required if companies in all industries (in industry-specific hubs everywhere) are to grow by acquiring startups rather than hiring.