And also cross browser support for the spec in general - eg desktop Safari doesn't implement that date picker, or any special treatment of input type="date" at all.
Does that mean only fully up-to-date macOS gets it, or do Safari versions move independent of the OS?
In rare cases, Safari features require a capability only available on the latest macOS.
And iOS 14.5 (well, 14.5.1) is also current: https://support.apple.com/en-ca/HT211808#1451
But we'll have to wait a few weeks to months before all Safari users upgrade and see the latest improvements.