Hard question to answer. I have a sub 3% mortgage now, had refinanced twice (from 4.625, then from 3.750), and this is my first house. When my rate was 4.625%, I still wasn't that close to considering making extra payments. In the "considering-buying-a-house" years of my life, the going rates for mortgages have never been that high compared to historical mortgage averages/variation. Part of me wants to say that at 7% I would start paying extra as that is higher than what my remaining student loans are (6.8 or 6.55) and the long-term real market average returns around 7% but would I really? I'm not sure, I haven't ever been in that situation.
I do like the current level of cash flow my household has and feel we are "consuming" the amount of house that is right for us (2BR, ~1000 sq ft) currently. Provided the interest rates were below 7% when we bought, the amount of house we were going to purchase was inelastic as we would never be "tempted" to purchase more just because the rate was low, if the rates had been higher then we'd either have waited or started reducing the amount of house we were in the market for. If the going mortgage rates were 7% or 8% and we were in the market for a house to own, would we really pay extra or would we be investing more with the assumed market opportunities or would I change from a 30 year to a 15 year mortgage or would there be an interest rate that we would simply wait to pay cash or simply just rent? Hard to say as higher rates do limit buying power via cash flow. Also, there is a big difference in the style of pre-payments to a mortgage. E.g. the household that makes the equivalent of 13 total payments in a year (1 extra) is different than the household that 18 total payments (they pay 1.5x each month) in a year. So two households both might be pre-paying something extra but it could vary enough that the household making small prepayments might be more similar behavior-wise to a household who is not pre-paying at all rather than the household that is aggressively making pre-payments.
For n=2, I have two sets of friends who have removed themselves from the current housing market due to the mortgage rates. One household sold their house in August and is going to rent for around a year or so while they can do more research on the areas they are going to live in and hopefully have a lower mortgage rate at the time or a lower purchase price (if not, then I'm sure they would either change their budget or continue renting for longer or some other contingency). The other set of friends were already renting and are going to continue renting for now.