It seems like he could have accomplished that without signing an agreement to purchase Twitter - especially one that waived due diligence.
1) Tweet things like "I should buy Twitter", "I'm working on moving money around, finding investors, and freeing up money I have tied up to buy Twitter", "Hate selling Tesla, but we need a free speech platform. People will be getting bargains on TSLA!"
2) Sell the Tesla stock he wanted to sell.
3) Make an insulting offer for TWTR at a low value with all sorts of contingencies.
He wasn't planning on finalizing the purchase? When you aren't planning on finalizing the purchase, you put in all sorts of contingencies. You don't waive everything.
I'd say he tried to back out after the market started turning. It became clear that a lot of ad-based platforms were going to be facing some hard times ahead and interest rates started climbing.
I mean, if he'd waited a few months to make his "I want to buy Twitter" play, he'd been able to have offered a ton less. I think Twitter's board of directors went from "we're going to fight Musk" to "Musk must buy us" because of how the market turned. Had Twitter's board "drunk the kool-aid" when they were fighting the buyout?
I think it's in part a case of bad timing. In April, people were paying $130 for GOOG. A month later it was only $113 and now it's $85. META was $210 in April and now it's $89 (their story does have some complications around metaverse stuff). In November 2021, people were paying $54 for TWTR. In January when Musk started buying shares, Twitter was in the $30s. Without Musk's stated buyout offer, Twitter shares probably would have sank like Google or Meta's. Musk probably realized that he wasn't getting Twitter for cheap offering $54.20/share (below their 52-week high), but actually way overpaying given market conditions that were rapidly declining.
Twitter's board of directors wanted to adopt a poison pill to prevent getting $54.20/share in a hostile takeover.
I think it's hard to argue "it was just a ruse to dump Tesla stock". You don't waive due diligence if it's a ruse. Twitter's board wouldn't have been so hostile to it if they thought it was a great price. It's more just that the market conditions shifted a lot over the Spring, Summer, and Fall this year. If Musk had waited 6 months to make the offer, he probably could have bought Twitter for $15-20B instead of $44B.