That's true, the longest I lived in the same house was for 19 years.
As for my sympathy for grandma and grandpa, the idea that they are now forced to live in a box on the street corner is absolute laughable bullshit. Remember after all, the reason why their property taxes are going up so much as to send them into this imagined destitution is because their house has enormously increased in value. While my heart breaks for these people and like all good Americans I hate these evil hipsters (who have to live with 5 roommates because grandma and grandpa wouldn't let the city zone for greater density), I bet grandma and grandpa can salve their hurt feelings due to the enormity of the financial windfall that will by itself eclipse what most Americans spend a lifetime attempting to save.
Well I can't speak for other laws but I personally see little value in taxing someone less based on how long they've lived at their particular address. What that does is shift the tax burden from older residents who are (generally) better off financially onto younger, less wealthy residents. It's the opposite of what we should be doing.
Wealthy people tend to be older but seniors don't tend to be high income but rather fixed income. The key to being able to retire & get out of the way is low overhead. The problem is that cost increases over the years eat into that in no small way.
I'm still struggling to see the huge problem here. Those people are being 'taxed out of their homes' because something they bought for $50,000 is now worth $600,000 or more. Maybe the right answer is to say 'sorry you have to move, here's $600,000 as compensation.'
It'll cost them $600K to buy another in the same area.