Many cities have overly-restrictive building codes that prevent adequate housing from being built, which raises housing costs.
Our immigration rate is too high for the amount of new housing units we build, which raises housing costs.
Many businesses have taken a hardline stance against remote work, even for jobs where it would make sense. That forces people to live in areas with inadequate housing, which raises housing costs.
Existing housing is being increasingly purchased by multibillion dollar companies for rent-seeking purposes, which raises housing costs.
There's really no one-size-fits-all solution to the problem, but slightly reducing the immigration rate, limiting corporate ownership of detached single family homes, incentivizing remote positions, and forcing cities to approve more new units would almost certainly improve the situation.