There were a few shifts that happened:
1. Musk bought twitter
2. Musk, despite being the wealthiest person on earth and running companies that are genuinely fascinating, has nonetheless—against overwhelming odds—been considered a loser.
3. Because of (2) and his fragile ego (part of the reason he was widely considered a loser in the pre-Musk dominant circles) he went hard to the right. Petty grievances, anti-free speech, “burn it down”, etc.
4. Twitter made changes under Musk that compensated large accounts based on the number of views or engagements.
Effectively a rev share for ad spend
5. Because Musk can massively amplify content and has a fragile ego, aligning yourself with Musk’s pet issues directly affects income for influencers. Accounts in the other direction can be demonetized and deprioritized on feeds.
This has led to large accounts, in the run up to the election, being very vocally trump even when they’ve had publicly leftist leanings in the past. It wasn’t a shift in policy positions. It was a shift to ragebait and memes that were more likely to get Elon’s attention and retweets.
So it is both pretty clear and a result of active decisions in one specific direction. We don’t need a multi-year quintuple blind study by esteemed Ivy League research fellows to do the basic observation and deduction of the situation.