That’s correct, for some reason it not only requires Safari v14 but also requires MacOS 11 (Big Sur) or later:
That said, Apple traditionally has very high adoption rates for new versions of their OS and it looks like Big Sur is compatible with some fairly old devices:
- MacBook (2015 or later)
- MacBook Air (2013 or later)
- MacBook Pro (Late 2013 or later)
- Mac mini (2014 or later)
- iMac (2014 or later)
- iMac Pro (2017 or later)
- Mac Pro (2013 or later)
https://support.apple.com/kb/sp833?locale=en_US
Apple is known for having very high adoption rates for new OS releases (much more so than Windows) so I would imagine the majority of MacOS users are running Big Sur or later and/or using something like Firefox or Chrome.
There are metrics online that reflect this trend, although with the release of Big Sur it became difficult to accurately measure — so these charts incorrectly show Catalina as having ~88% market share: