If a family is renting in the same place for decades, that is their problem. The moment you realize you are going to stay in one place for an extended period of time, there is no reason to continue renting. Sure, not everybody can purchase their dream home. But they can purchase something small, build equity, and upgrade in the future. The government also has programs to help first time buyers, especially those with less income.
Again, the primary reason to rent is so you can relocate. If you are not planning on relocating in the 5-10 years, you should own, or be working on owning.
Furthermore, the landlord is taking on risk (risk of the market moving against him, risk of the tenant not paying him or the place remaining unoccupied after a tenant leaves), is paying property taxes, insurance, is responsible for broken appliances, and is also often taking on a loan with higher interest rates.
Should all of this be provided for free?