While this is difficult for each of them and their respective landlords, the bottom line is these tenants were lulled into a false sense of security. My guess is they figured they would be able to stay until THEY wanted to leave (Stories say they were friendly with their landlords but one landlord died and the other sold the building). When you don't own, you don't have control, it's that simple. You can get lawyers and go to court and kick and scream but who wants to end up in that place? The only way to have control over your life and where you live is to own. When you own no one can kick you out...you can live there until you die.
Now if you don't pay the mortgage the bank can evict you but this is why we buy units as our first purchase. If you buy units you are living small, collecting rents and paying only part of the mortgage yourself. Living small will allow you to live large in other areas of your life. Living small (below your means) makes life easier. 72% of Americans report money as the #1 stress in their lives.
Back before the mortgage meltdown some people were living large...buying houses they really couldn't afford and they lost them...they were evicted and foreclosed on. But when you own units...the tenants (like those in San Francisco) are buying your property for you. Once it is paid off the tenants will still pay you rent. When you no longer have a mortgage and the tenants are paying you rent it would take a natural disaster to make you have to move or be homeless but guess what...you'll have insurance for that!