I particularly dislike Musk, but destroying 15 years of brand recognition is suicide. And, even more so, it makes so sense to do it. I can only think of a few major brands that have ever attempted a rebrand.
For example, UK courier company Hermes rebranded to Evri to escape it's horrible reputation. (Evri now has a horrible reputation)
PC World rebranded to Currys PC World when they were taken over... By Currys!
A few companies have shortened their names to modernise, but kept the bulk of it. A supermarket called WM Morrisons dropped the "WM", although that is technically still it's legal name.
Holiday company Thompson rebranded to Tui to try and revive a dying business, modernise and expand their markets. They were just about successful.
Anyway what I'm getting at, is rebrands are risky, expensive and difficult, and are only done for a real purpose. Musk has just done his on a whim, for zero reason.
The guy is mad, and by some marketing experts account has just flushed a $10bn brand down the toilet.
Anyway, if I brought another community then I'd likely do a Google and keep the brands separate - but under a header brand (like Alphabet). One of the cycling websites I read has done this.
Brand recognition (and consistent URLs) are everything on the internet. I actually rebranded about a week after starting my website because I didn't feel it fitted - but then I had no users so it doesn't count lol 🤪