I agree that Tesla having only EV's is a restraint. They also have no debt and I think they will remain the leader in the market for the foreseeable future, such that the market is. Tesla's primary issue is owners bid the price up to unsustainable levels. Getting rid of Elon won't fix that - if anything it hurts it, but they will do so anyway and it won't help.
There are lots of companies in that boat right now due to mutliple expansion from covid money printing. Tesla is just the current poster child.
As for GM, well there the same price they were at when issued in 2011 - not accounting for inflation and not accounting for all the debt they took on to buy back stock. So I guess once you hit rock bottom its only up from there.