care to share any sources? or did you just make this up?
This site does a pretty good job: https://sfciti.org/sf-tech-exodus/
Article from the SF Chronicle: https://www.sfchronicle.com/bayarea/article/Austin-COVID-tec...
Hopefully that addresses your question as to why I hold this opinion.
According to wikipedia/some google-fu SV has just above double the high tech jobs as Austin