Well... I too have a huge fondness for the International Space Station, so I understand your spirit of wanting to save it for future generations!
I certainly hope they do save it: for me a higher parking orbit would be better than destroying the thing in a fireball re-entry.
That said... of all the things that SpaceX could do with that money... I hate to say it... but... buying the International Space Station is at the absolute rock bottom list of priorities, for me personally at least.
ALSO: if NASA and the station partners ALL agree that it should be a future tourist destination (which Russia won't agree to, I can guarantee you that!), then they'll all arrange to simply boost it into a parking orbit, and leave it there as a tourist destination for any companies that will want to fly tourist flights there in the future.
There's really no need for NASA and the station partner nations to hold a gun to the station and say,
"Now look here SpaceX: either give us the money, or the station gets it! We're not bluffing!"
So no need for NASA to go around siphoning off or sucking away vital funds from important private companies like SpaceX that are working on far more important things for NASA.
Finally... 1000 years from now, space will be filled with billions of space stations... and tourists will be visiting things far-more exciting, such as the long-lost alien civilization ruins of the Trappist solar system! (Something like that!).
Either that: or humanity will no longer exist.
But ya, as for visiting an old musty decaying space station in an era 1000 years from now... it will only be a tiny-tiny-tiny historical-nerd group that will want to do so. For example: I'd love to visit the museum of old computers, but virtually no one else in my social circle wants to travel that distance to visit such a museum!
PS: not to mention that old proverb, of how we will seem like ants compared to a hyper-advanced civilization such as the one that could be present 1000 years from now.
Are you highly motivated today to travel and visit a museum fossile-relic of an old ant farm?
Some entomologists are! The vast-vast-vast majority of people, not so much.