I know the claim recently was that there were more unoccupied homes than homeless people. Even if you factor out the undesirable/impractical ones, I'd expect if we had some means to unlock that capacity, it would glut and crash the market down to (much closer to) affordability.
It feels like this is one of many problems that are trivial to solve in the abstract, but intractable as long as we worship private-property rights. A simple fix would be an >100% annual value tax on unoccupied dwellings. The vacant-50-weeks-a-year vacation house, or the 'investment property' you're holding to sell in a few years, becomes an instant financial grenade, where it's better to hand the deed over to your pizza delivery guy as a tip than to be not living in it when the tax bill comes due.
I'm not sure RE is overvalued. There's a shortage of houses at a time when Millennials (the largest generational cohort so far) are hitting peak household formation.
> Now, there is money that holds its buying power
Bitcoin peaked at around $64K in April 2020. Now it's currently at $38K - it was down to about $30K a month ago. Seems pretty volatile for something that "holds it's buying power".