1) The standard deal gives much more money to startups and so based on what I've see on Crunchbase many startups are simply not raising seed rounds post-YC. So that negates the need to move to a VC hotspot like SF at least in the beginning.

2) COVID has demonstrated that you can make remote work and that a sizeable percentage of employees (especially in IT sector) will only accept a remote role. Many startups simply won't have offices or headquarters at all.

3) As was pointed out by Jason Calcanis last week a lot of the people who publicly told the world they were leaving SF for Texas, Florida etc have been quietly moving back. Despite all of SF's many problems there isn't anywhere else that can replicate the critical mass of talent and network that it provides.