Safari 16 is not a reasonable target for the vast majority of developers.

Apple tends to support older iPhones in newer versions of iOS, and iPhone users upgrade their software a lot. The most common target is the last two major versions because people using older versions are so rare. Every iPhone released in the last nine years can upgrade to iOS 16 to get Safari 16.

You can download a CSV here to explore the data: https://gs.statcounter.com/browser-version-market-share#week...

Baseline’s support window for “Widely available” is 30 months and Safari 16 is almost twice that age: https://web-platform-dx.github.io/baseline/

If it makes sense for you to spend time supporting 0.25% of users rather than spending that time on the other 99.75% of users, then support Safari 16. Everybody else should avoid incurring that opportunity cost.