I don’t think the 2-3x as much in 15 years time is likely to be true. When interest rates start out low there is much less scope for appreciation than when they start out high. So if you buy when mortgage rates are at 3% you can’t expect the big gains you get when mortgage rates fall.

My personal rule of thumb is that rents remain fairly stable as a proportion of earnings under balanced supply and prices are then a function of rents / mortgage rates.

Over the past 15 years median household income has gone from $50k to $80k while mortgage rates more than halved from 6.5% in 2006 to 3.1% in 2021. Most of that 2-3x increase is from the fall in rates.