Well you're 'renting' but keeping all the capital appreciation over 20+ years (oh sorry, forgot what forum I'm in - prices will have crashed by then...)
Seriously, an approach I think will be used by more and more people, voluntarily or not, is to downsize on reaching end of mortgage, therefore clearing mortgage which should be a small % of equity by then. Benefit is having lots more cash every month that you're not spending on Repayment. If you make money through business, investment etc.. then you can clear it that way in 20+ years
Neil