"it's too slow to save 300K today...we need the fast path to generate wealth by using the bank's money..."
This is the crux of the problem.
People who want to be responsible by "saving" cannot save it quickly enough for the price rises of a house, because others are using "borrowed" money. Lots and lots of borrowed money.
Where someone responsibly beleived $300k of borrowing with a strong deposit is bidding against carefree $500k borrowed money with a weak deposit.
