I see housing prices have been growing enormously in the last few years, but the appartements are exactly the same as they were twenty years ago.
I don't see how I can get more 'value' out of an appartement that is older, not renovated, and costs twice as much.
I mean that people get more benefit from it. What specifically counts as a benefit depends on the person.
> the appartements are exactly the same as they were twenty years ago.
This is going to depend a lot on what area you are in. In my area, much of the housing is fairly new, because either old housing was torn down and replaced, or housing was expanded into land that used to be something else (mostly farms or woods).
> I don't see how I can get more 'value' out of an appartement that is older, not renovated, and costs twice as much.
Any capital investment depreciates, and eventually you will need to reinvest in it in order to continue getting value from it. But suppose the average dwelling lasted 50 years before needing to be renovated or replaced, instead of 20. That would be an obvious benefit, even if the original purchase price of the dwelling was higher; in fact many people might be willing to pay the higher price in order to get a dwelling that would last so much longer.
Of course I understand that this is not what we currently see in most housing markets. But I think it is highly relevant to the question of whether "make housing cheaper" is always the right goal if you're trying to reinvent housing.
I don't think this is a good view to take as a fully general statement. People invest capital in real estate because they get benefits from it. If the benefits they get are worth more to them than the benefits they would get from any alternative uses of the same capital, then putting that capital into real estate is optimal for them.
> it'd be far better to try to make housing/office space cheap and have people invest the extra money in productive assets.
If spending more money on real estate increases its value to the people who use it, then it is a productive asset. I think you are taking too narrow a view of what "productive" means. Instead of seeing it as "make housing/office space cheap", I think you should be thinking of it as "make housing/office space give more value for a given investment". In other words, don't make it cheap; make something people want. Making it as cheap as possible might not always be the best way to do that.