I don't feel that you made an accurate comparison. You car is made by $X manufacturer but in this case all the aftermarket addons which you have purchased at a myriad of other locations (i.e. window tint, car stereo, cup holders, car chargers) will also pop in and make their own changes.
So in this case the store that sold you your Clarion deck will stop by and fix your stereo but also leave a GPS tracker or mute your system to play their own wares.
Updating Chrome is one thing because Google doesn't want to mess with the PR nightmare when someone finds out their update streams popups like mad but some one off developer who makes a LOL Cat extension probably isn't making any money to begin with will have no problems bending one way or another for a couple of quick bucks. Both get equal say over the clock cycles on your system. Does that really make sense to you?