Although there have been occasional very brief falls in house prices, the trend has always been relentlessly upwards (see first graph below).Inflation has to be controlled. The main method of doing so is to put up interest rates.
When that happens, it's big bust time, as all those with mortgages they can currently just about barely afford suddenly won't be able to afford them.
In terms of 'affordability', it's interesting that throughout the 20th century, average house prices remained largely unchanged, at roughly 4-5 times average annual earnings, but have risen to not far less than double that in this century.
Unless something truly dramatic happens/changes (in which case we'd probably have greater things to worry about than house prices), I don't think anyone should fear that house prices are going to fall in the medium or long-term.
Kind Regards, John