That isn't true, or at least it doesn't need to be. Someone with a 4*salary mortgage, about the maximum you can get on normal terms, will be paying about
16% of their salary in interest at current rates. I would think that most people could afford to pay 25-30% of salary in repayments without too much strain (after all that would have been the repayment a few years ago when base rates were at 7%), i.e. they can repay maybe 3-4% of the mortgage even in year- At that rate the mortgage will be more than half gone in ten years. Also salaries in general are likely to grow with the economy, i.e. maybe 4-5% a year, and the salary of many people will grow faster if they get increments or promotions, and again over ten years that will make a substantial difference.
Yes - but with low interest rates it shouldn't be hard.