Chrome for example has a ton of limitations:
https://getpolarized.io/2019/04/05/Google-Will-Kill-Chrome-E...
If you want to do anything significant you have to get their 'permission' and at that point they throttle your extension release updates.
You can't just push an update immediately that gets sent out. They take a week to approve your extension.
This might sound reasonable until you realize that a week is an eternity for a continuous development shop. That might as well be a year.
ESPECIALLY if something is broken.
Imagine if you had a bug that destroys data and you need to rush out a fix. Nope.. You need to wait one week for that to go out.