You might not like or trust Musk and that's fine, but what he says is no different from what actual experts on the matter say. I challenge you to find a single expert who actually has some expertise in the development of AI (and automation) who would claim that human labour is irreplaceable. Maybe you could find a few of such a decade ago, but nowadays most agree that pretty much every area of work will get replaced eventually.
And given that progress happens exponentially, saying that we need another 100 years for this to become a problem is a massive downplay. Sure, there always be *some* jobs left, but if you can't have a functioning society where the majority of people have nothing to do.
This is not really about elon because if you look at this everyone is entitled to their own opinion their are people that might be in support of the use of AI and even if you are not in support most company are very much interested in the use of AI because it reduces cost they don't mind spending a lot of money for them to aquire. Just to cut down the cost of labour. The only reason I see why humans are important is that Ai can have default and act on its own due to errors. Imagine have Ai even in the military just imagine what will happen if Ai should malfunction their will be lose of life because they don even have feelings so they will do things, without thinking wether humans will feel hurt or not. That is why we are different from them. And that is people are not in total support of it, and even elon uses AY, especially in tesla. He should stop his criticism.