Refreshing Musk is not mentioned here. He says some stupid stuff but he has made his money actually making inovative products that move the world forward. So dumb to hear him talked about as an oligarch.
Plenty of others making their fortune through rent seeking means that could be focused on.
I think he's an oligarch because he uses his influence to affect politics (and in a very nasty way, like demonising immigrants and lgbt members who just want to be themselves). Using his fortune and influence to influence politics is what makes him an oligarch.
How these people made their fortune (whether it's useful or not) has no bearing on the definition of an oligarch.
Plenty of others making their fortune through rent seeking means that could be focused on.
How these people made their fortune (whether it's useful or not) has no bearing on the definition of an oligarch.