So you think Tesla and SpaceX will implode, leaving Musk penniless? Because that's where his 'insane wealth' comes from. However I suspect that a lot of legacy car makers will be throwing in the towel before Tesla, and Boeing might go sooner too. The big question marks are over the Cybercab and fsd, and the Optimus robot. Tesla is sinking an enormous amount of R&D into those projects. If they don't pan out it might sink the company, since increased competition from other EV makers is bound to reduce their market share. OTOH if they do pan out it could be huge. Musk has never had an aversion to risk, and so far it has worked out well. Just luck? Or is there some mad genius in it too?
You say it's dependent on finding new investors - I don't think that's true. AFAICT Tesla and SpaceX are self-funding now and don't need new investors. Tesla is a public company so its 'value' is determined by the share price. So long as they seem to be doing well the price will stay up.
Other big players in the industry are now saying that Tesla is leading the way in autonomous driving, AI and robotics. Their grid scale battery storage business is growing exponentially. Last year they managed to hold their own in EV sales against BYD, China's largest EV maker, despite pundits saying they were finished in China and the EV 'fad' is over (hint, it isn't). They have nearly completed the factory that will be making the Tesla Semi, which is also being trialed in Europe.
Of course all this could go bad making Tesla go bankrupt, but they are in much better financial health than many other car makers. Nissan just announced a merger with Honda to stave off the inevitable, Stellantis is in trouble, Volkswagen is crashing hard, BMW stock is down 22% from a year ago (down 33% from the peak in April 2024).
But who knows what the future will bring? If China invades Taiwan, what will Trump do? What will Putin do when he sees the Ukraine war is lost? If half of Los Angeles can go up in flames in the middle of winter, what will summer bring? Bird flu is decimating diary cow numbers and killing chickens causing the price of eggs to skyrocket, but that's nothing compared to what we could be facing if it jumps to humans. If bad things happen and the global economy crashes it will probably be game over for Tesla and SpaceX, but Musk won't be the only one losing his shirt. However without a global catastrophe it seems pretty likely that he will remain 'rich' for the foreseeable future, and not by 'finding new investors faster than he can annoy his current ones'. But hey, keep believing that narrative if it makes you feel better.