Especially when free cash flow or an owner's liquidity is required quarterly by creditors. Even that is a big simplification: Elon has co-investors in what, to them, is a prestige investment. Getting diluted in down rounds dissipates a lot of prestige, so it is likely that any of Elon's money to prop up Twitter comes in via loans. That money comes from margin loans on TSLA which has a precarious P/E ratio. SpaceX's valuation, which is based on the post money valuation after a Saudi wealth fund bought 0.5% of the cap table, is very high but it's all illiquid. Starlink should have been ready to spin off at a fabulous valuation had it met subscriber goals, but it is about 10% of the way to 2023 goals.

Elon is an extremely rich man, and people like that have hobbies. The Washington Post, for example. But that cost about 0.2% the price of Twitter. Probably less than Bezos's yacht.