It depends on the appreciation and in turn the property taxes. I own my house outright. Completely paid off. But the increases in property taxes is forcing us to sell and move, likely in the next 5 years. Too bad, love the neighborhood and the area.
Honestly, this is not a hardship but a nice problem to have. I grew up chronically poor and I feel fortunate and grateful that we have a comfortable home that is ours with equity while a lot of people have housing insecurity.
I agree on the windfall part but selling to get that money is not that simple in the current real estate market and political climate. ie you got to live somewhere... and everywhere you desire is expensive.
So yeah nice on paper that the house is worth a lot more than we bought it... but that value matters if we sell and move. There is a lot more to that decision than just the property tax, however it sort of putting a time limit to it.