It also depends on what you mean by losing one's home. That's not an issue for people who would sign the written agreements. Afain, we want a disincentive to informal agreements, including from renters and squatters. I'm not sure how you can equate loss of ownership with loss of temporary use.

There will always be many people taking "illegal deal" as sometime you have no other other solution, or other solution are even worse. And many many landlords are doing illegal things, including public housing.

Tenant don't have the same bargaining power / freedom / agency than landlord. Fighting illegal stuff that do landlord is long (usually longer than kicking out a squatter) and difficult. And you have little incentive to do it as a tenant : being in a fight with your landlord = being sure to have problem down the line

My feeling is that your comment ignores this asymmetry.

These are enforcement problems, not squatter problems. As you've said, the things the landlords are doing are already illegal. In the US we have Attorney General offices that will handle housing cases on behalf of tenants.

Both parties can benefit from better enforcement and written and recorded leases. Penalties for landlords leasing without recorded agreements may be more easily enforced that under the current system.