This is where it gets complicated. The world needed SpaceX. Having satellite launches be pretty much only in the realm of national governments was a bad thing, long term. It's not like they organised themselves to avoid space junk, it was a fucking Wild West anyhow so reducing launch costs and opening it to more business could only be a good thing. And I have to give His Muskiness the credit to put his money where his (incredibly large) mouth is. That said, beyond the initial investment, I think SpaceX is mainly successful
despite Musk. They do, quite famously, have a fulltime member of staff dedicated to handling their most senior investor and stopping him from meddling too much. The guy is loco, no doubt, but there are some instances where you need a loco investor to kick start things and SpaceX is a good example.
Tesla is a bit greyer, as Musk didn't start that himself but he did make it possible from them to actually get to market. The world needed to see an electric carmaker succeed to get off their arses and do something. It looks like, in the long term, Tesla might get buried by the Big Boys but they'll have done their job. Electrification is probably 10 years ahead of where it would have been without them. Again, they needed a crazy investor and there he was.
But the fact is this guy was throwing darts, blindfolded, at a dartboard full of his childhood obsessions. These are his pet projects. You've
seen his other pet projects (including his unfortunate children) and you know the guy is unstable. If not edging on Evil Badguy intent on world domination. I'd personally have nothing to do with him, but I have to acknowledge showing up with funding where it was needed for some truly disrupting technologies. That's how history works, in the main. There are a few things that slowly evolve, but most of them move in big bangs (evolution included!) and there has to be something to drive it. Just be happy it's a loony South African and not another World War that did it.
As for his other projects...
You can only be lucky so often.
So my epitaph would be: "Elon Musk. Tosser. Spent his inheritance mostly usefully."