You can disable auto update of chrome. And you can switch your default browser. And you can install a system wide adblocker. And you can get a chill pill.
System apps can be updated through Google Play (or any other channel) just fine. The version bundled with the system is just the baseline you can always revert to.
During a system update, the system apps only get updated if you don't already have a newer or same version installed (no automatic downgrades).
I already know what a system app is and how updates work for them. I was questioning what he meant by having Chrome as a system app and claiming years of OS updates. His comment did not make any sense.
They were talking about old iOS getting a system update just to update WebKit/Safari which then generated quite a few news articles about how long Apple supports old phones. Their comment made perfect sense, they just didn't know how Android works internally.
Re-reading the parent comment, I'm not sure if it was sarcasm or ignorance. I guess you should have written this comment to my reply. And the Chrome update thing to that commentor. Anyway, thanks for the clarification.