If not by SSM, the Space Shuttle will continue to exist on computers by other simulations for decades I think. But I guess SSM already will last VERY long
It's sad that I did not witness one of the greatest eras of manned space exploration: Apollo. But I'm very glad and actually thankful that I've got the chance to at least witness the Shuttle program from beginning to end, although I was just two years old when STS-1 lifted off. But I remember being interested in it already when I was in elementary school in the mid 1980's, initiated by the accident of Challenger. I remember the broadcast on TV as if it was yesterday. Being thankful to be a witness of that great era of space flight, I'm also thankful for SSM as it will keep up great memories.
But what I'm often asking myself is: what would happen in about 100 or maybe 500 years? Life is rather short. I wonder if humans will still be interested in "old" stuff like the Shuttle, or just watch the remains in museums but not knowing a lot of it beside just a few historians will do. But by that time, I think almost everybody will be able to take a cheap ticket for space planes, that take you from New York to Tokio in no time on a suborbital flight, whilst having a small snack and experiencing zero-g for some 20 to 30 minutes before landing
I'm confident that subsonic, "low" atmospheric passenger flight will become obsolete in the long term... Concorde was just the first small step, which appeared prematurely.