What you're saying, which is a good point, when you say that shelter isn't optional, you can phrase that more precisely as "owning property is a hedge against variable property prices". It's true but there are other ways to hedge this, eg. Long term rental contracts, limited rent controls or owning specific derivatives all reduce this risk. There are societies that run like that, eg. Germany.

Some stocks can go to zero, some are very unlikely to and most portfolios have things that are very unlikely to flatline like govt bonds. Well i don't mortgage although i could, and I do save so hello you've met your first. The idea that we need a bank threatening to throw us out of our houses to enforce responsible saving is infantile and grotesque.

General criticism of the finance sector is a bit too off topic for me to engage with.