"Buying a house" isn't the same as "owning a house". It simply means having a mortgage, which is traded up in the bond market, with hedge funds (+derivatives, futures, and credit default swaps) betting against your ability to make those mortgage payments.

I live in NW Arkansas, in the shadow of W-M, where demand for housing has out-paced a building market based largely on exploiting Hispanic workers with no collective bargaining, and very little in the way of practical English language skills.

Over the past year, materials costs have ratcheted up, OSB is now $40+/sheet, up from >$10 a year ago. The price on lumber from Canada has also gone up, due in part to Trump's mis-guided trade policies. Along with high demand, volatile material costs contribute to the increase in housing costs.