If Elon hadn't bough it, maybe the Twitter would have been fine without significant restructuring. But now Twitter has to service a significant part of the debt created to buy the company, and thus has to generate more revenue.
Elon bought Twitter because the Delaware courts are not the milquetoasts he's accustomed to (at the SEC).
Edit: my suspicion is that Elon expected the Twitter board to rebuff him, and he'd walk away calling them names for the rest of his days - and then the market dropped, removing resistance from the board (if any existed). This was capped off with Delaware courts showing every sign of muscular oversight of contract law, with Twitter reveling at the chance of embarrassing Musk and people in his orbit and getting bought off at a now-overpriced amount. It was a perfect storm.
