Please feel free to look up my bio in my profile. Then go play around with a basic mortgage calculator online. You will find that as you extend the length of the mortgage, the payments will approach the interest only payment level.
Also, in the late 80s, early 90s, interest rates were 15%. 10% is just slightly above historic norms.
It is 100% possible to reimburse a mortgage at 10%. Millions of people have done it.
Any basic mortgage calculator would show you that the mortgage is not viable, the interest would accrue faster than it can be paid back. The duration or the rate must go down.
In the 80s, the interest rate was higher and the duration was lower. People didn't make a 30 or 40 years mortgage to buy a flat.
It's a single equation with 3 variables. The monthly payment, the rate and the duration.
The payment is about 50% of the typical salary in the area. The rate is set by the economy. The duration is determined by the two other variables, it's not adjustable on its own.
If you raise rate, and assume pmt, fv constant you must increase n or decrease pv. My original point was that pv (loan value must come down) secondarily, n increases.
The duration decreases when the rates increases. It's not possible to reimburse a 30+ years mortgage at 10%.