> Hence the loan is only enabling demand.
> The only reason prices change is because supply or demand changes.
We are living in year 16 of the era of government pushing loan prices lower than the market would set them. 8th year since they've been pushing the loan pricing down VERY hard (ie. essentially to the zero bound, where you're only paying for the (also artificially lowered) risk of the banks, admin (ie. people employed to check payment and tax and ...) and a small profit margin for the banks).
While of course it is not really known how high the market would set loan prices, it seems the long term average is 4%. Since we've been below that for a while, let's call it 6%. Add the 3%-4% of risk, admin, tax and bank profit and mortgage rates should be somewhere between 8% and 10%, if you have really good credit.
What would house prices be with 9% interest rates instead of 3% ? That's quite normal a rate for mortgages, long term. My back of the envelope calculation says that they'd be, with the same monthly payment, a bit more than double what they should be, in market prices. Prices should be 60% less, or put it another way houses are 120% overvalued.
At a very optimistic 7% (the long term average), house prices would be about 45% less, or they're 75% overvalued.
(example calculation: with 3% mortgage payment, a 4000$ monthly payment will get you 1.12 million dollars, at 9% it will get you 0.52 million dollars, or a little less than half. At 7% it will get you 0.8 million dollars, or 45% less)
Hence I strongly disagree with your notion that house prices are determined by supply and demand. House princes are as high as the government can get them, and damn the consequences.