What is those people's second biggest purchase which is also usually done with debt? Does anyone believe that the government should enact policies to ensure that car prices always increase so they would be a better investment? Houses obviously have a longer lifespan than cars, so I'm not suggesting they should necessarily depreciate the same way, but there is also no reason housing should always be appreciating.
We have this idea that the price you sell your home for should always be higher than the price you bought it for. There is no reason for us to preserve that idea beyond the fact that people have now internalized that idea and plan their financial lives around it. The longer we allow that to continue, the harder it becomes to change, but the idea itself is not some fundamental requirement of society.