While it's possible that Google hasn't said they'll be doing the updates separately for the browser there's no reason to suspect they wouldn't do that once LaCrOS was fully implemented -- after all, it works under Linux.

The comment I submitted only went so far as to say they started doing "that", referring to the parent's post about decoupling and providing separate updates.

If "that" is referring to both, it's incorrect. Google has said they will be "well into 2024" without any benefits brought by LaCrOS. That includes any theoretical extending of the expiration dates.

Are you arguing that because they won't have something providing benefits until "well into 2024" that they have not started as of the time of my comment ?