He changed the entire industry, not only Tesla. It is possible, that in the grand scheme of things, Tesla will mean nothing. However, there is nothing to suggest, in fact there is a lot to suggest the exact opposite, that the big brands like Toyota, WV, Daimler etc would have switched if Tesla didn't essentially force them to switch. Also, the work on batteries has been immense, which will eventually force the other industries (like airplanes) to switch.
There is more stagnation, rather than getting poorer, from all I know. The gap is widening, true. I personally don't care about that too. As I said in a previous post, if everyone gets 5% richer, I would take the top x% getting 500% richer without a shadow of the doubt. The point, to me, is that the lives of people should improve, not that everyone should have the same wealth, or no inequality to exist.