SF won’t become Detroit. I credit SFs culture for a lot of the innovation seen here. Not sure if it’s gold rush energy or what, but there’s an unparalleled optimism and just people looking to reinvent themselves.
A lot of that optimism that makes SF vibrant is driven by the immigrant population [1].
The exodus that OP prefers, if it comes to pass will be lot more them than the 2nd-3rd gen residents
[1] immigrants to San Fran, or California or the U.S.