I know, because I *did* that update for TYPO3, which is a huge codebase. It didn't force a rewrite. It didn't take years to do. It took me maybe a month or so to fix nearly all PHP 8.0 compat issues. In a 20 year old codebase still built on arrays.
So... really, where is this idea that you're forced to "completely rewrite" code to be PHP 8 compatible coming from? I genuinely don't understand.
2/2