Why would you even ask? Is this for school project? I suspect that many on this board, me included, will close before Phantom does (and I at least am 68 and in good health).
I am actually beginning to think that Phantom, Chicago, The Lion King, and Hamilton will still be open in a decade. Not sure re Mormon, which is clearly a monster hit and not sure if Wicked will benefit a little, a lot or not at all from the eventual movie, but -- if I had to bet $$, I would bet that Wicked will still be open as well. (Only Chicago is in slight doubt...it depends how they can keep the weekly nut down; Chicago is actually going to close 2018 as its highest grossing year ever...not sure how well its grosses are keeping up with its nut growth.