By some measures, we’re already there. Mortgage Daily News tracks mortgage rates based on averaging lender rate sheets each day, looking a no-points rates. They have 30yr conforming at 5.6% now, compared to 2.8% available in the summers of both 2020 and 2021. I’ll put a link to their summary page here, which covers many products and indices. If you click around, you’ll see the charts.As far as I can tell 30 Year conforming mortgages are about to hit double what they were at the bottom 16 months ago.
As I have said before, I think rising interest rates affect lower priced units more than higher priced units because those buyers tend to need higher leverage, and also tend to borrow further towards the maximum of their qualification limits.
However I think it's been underreported how many buyers have held onto their prior properties rather than selling them because mortgage rates have been close to zero. This has been a factor in low inventory because in the past homeowners trading up took a unit of inventory off the market but also added one, but lately only did the first. Soaring mortgage rates could reverse that trend.
PS I think it's hard to look at that Miller Samuel chart and conclude there is no relationship between mortgage rates plummeting and prices soaring. (But I'll also note the part of the chart before 2000 isn't great data: the Coop market absolutely crashed between 1989 and 1992, but the chart shows it at pretty flat. Pretty much all the reports back then were going off very small percentage of the actual transactions.)