If you are familiar with John Lilly (https://en.wikipedia.org/wiki/John_C._Lilly), you may notice some similarities with Musk. Lilly used/abused ketamine and began to believe in some form of extraterrestrial oversight of earth, something like that. Musk keeps tweeting about "simulation theory", and to me sounds totally deranged. He says he thinks reality is a simulation (batshit imho), and that boring simulations are cancelled, and only exciting ones are allowed to run (by whom..?), stuff like that. He's out of his mind. I am not choosing sides here, and Trump's behaviour is absolutely deplorable (again, imo).
Are you referring to Musk saying "The most entertaining outcome is the most likely"? It's just a joke, it's a version of Occam's razor — I can't find any mention of him arguing that this is genuinely how the world works.
I would not consider Musk as a researcher of the topic - he has not published any papers or even works on philosophical level, so you are giving Musk too much of attention - just like his appearance in Simpsons.
In regards to reality as simulation, well - the issue here is that definitions are not very precise. That simulation is reality to us. We have mind limitations, by which we operate just like animals have them and that makes our reality. I have experienced deja vu many times and the mechanisms to that might be linked that things are predestined - pretty much this is main belief, that all pre-Christian societies believed in and generally Christianity is not in opposition to that either - it just states that there is a free will to humans and that they must choose God over Santa and deja vu can be experienced only by saints that are in direct contact of Ultimate Being.
I don't know where Musk is getting his ideas, but what is mundane and boring to some might be exciting to others. Insects controlled by pheromones might be living most exciting life that there is.
I think I have heard some other ideas that most probably developed on the basis of ideas of Lilly. It involves reincarnation of souls in other beings. I'm not completely sold on idea(because that is presented as noble and next nuclear war is not under any definition), but that might explain why society is deranged as that right now, as current beings does not have noblest souls... though it can also be explained by many other factors. Though, the mechanics of transfer of nomadic souls would explain no need for transportation to reach all the other planets that have life, but also - that is not really what matters - we don't think that dinos had more importance over humans and to be fair humans themselves are just an episode in this Universe as well.
The idea of Lilly can be expanded - pretty much Universe can be just a playground for various beings to experience whatever - just like a RPG game or a live movie, where you can play a role. It does not necessarily require soul mechanism mentioned earlier. But it also does not matter for your existence - you are as real and important as you want it to be. Or don't matter at all and there is no reason or value for anything.
Regardless, your destiny is to live through this cosmic theater and experience Musk - do you like it or not. Pretty much your reality can also be formed by your mind and it seems, that Musk is very central part in it.