Plunging U.S. revenue at X risks opening up a "massive hole" on its balance sheet that Musk needs to plug to stave off its financial collapse.
Musk’s repeated outbursts against advertisers have dried up the main source of revenue for the loss-making company formerly known as Twitter. A recent decision to sue them for heeding his own advice to not buy ads on the platform hasn’t helped. At some point, he will have to provide a fresh infusion of cash to salvage his $44 billion takeover.
I don't know much about trading stock, but I do know SpaceX is not a publicly traded company. That means his buyers for those shares are super limited, so each potential buyer would likely be super wealthy and would have more say over the company than any one individual in the horde of public buyers that would buy up the Tesla stock. Plus, him needing to divest from Tesla might actually drive Tesla stock up a little (eventually), since he won't have as much control of the company as he did before. It seems he would still be the largest shareholder after the selloff, but this would close the gap between him and the next largest shareholder. He owns over 3x more Tesla stock than the next largest shareholder.
He's using Tesla, a publicly traded company, as a piggy bank and transfering wealth from it to the privately owned Twitter and SpaceX. This is stealing from Tesla shareholders but because they're fucking idiots they're just letting it happen instead of dumping their stock and suing.