You have a point actually,bitcoin would have still hit 100k with Trump being the president of the US or not.Although his victory gave a huge headstart to the rise of bitcoin  to 100k.
If the US had adopted bitcoin as their legal tender as El Salvador did it would have gone global and been the talk of the town making bitcoin even more famous and promoting its value amongst other nations creating a great influence and tempting other countries to do same.
Moreover, speaking of how bitcoin would be affected if El Salvador stopped giving support,from my point of view bitcoin would be slightly affected but it would be at the cost of El Salvador because bitcoin has greatly  contributed to the economic growth and development of the country.
I think they would not ever think of taking such drastic action because it would be a disadvantage.