Most of the housing bubble is actually a land price bubble. Land is only a long-term depreciating asset in shrinking cities, because demand for the land is decreasing.
The interesting thing about these ingredients that decide the multiple, is that they can turn sharply. If interest rates go up, and multiple starts to contract, at some point the belief that house prices always go up will be shaken, and instead of pricing in future house price growth, people will start pricing in future contraction.
Level of rents is a function of the state of local economy (broad salary levels, more or less) and house supply. Can probably broadly be approximated as GDP growth - so fairly low.
So at interest rates at very low levels and arguable on the way up, and growth expectations seemingly very positive, and economic growth looking shaky, it looks as if house prices may have more downside than upside.
1) the house itself (this generally depreciates)
2) land (this generally appreciates)
3) a retirement account with great tax benefits (this value can fluctuate based on local, state, and federal laws)
4) a ticket into a good school district (this value will fluctuate based on the the performance of local schools)
5) a ticket to partake in a thriving local economy (this value will fluctuate with the local economy, and has recently been shaken up by the rise of remote work)
Any speculation on real estate prices and whether or not we're in a bubble has to take these things into account.