Earlier quoted context omitted.
A single stable identifier would've solved the whole situation and Apple already had it with Advertising ID. Exposing that to the browser would've been enough so Safari could've been ahead of the curve.
"Solved the whole situation"? From what perpective? Completely killing privacy is not a solution, quite the opposite.
Making that available for apps and websites would've eliminated 99% of cookies and user syncing pixels since the industry could use a short-term stable ID to track engagement and conversions.