There is no one cause that leads to housing shortages, but tech salaries are a huge issue in and around tech hubs like the SF Bay and Seattle. And especially during covid, with remote work, the rich spread out to towns nearby and bought up all the housing there too and pushed out the locals.

That's not the government's fault (besides lockdown), it's because tech workers were way overpaid (and hence all the layoffs and salary deflation now).