The problem with this is crapware vendors existed before extensions were available. They were dirty hack modifications to the programs. They would introduce a

The problem with this is crapware vendors existed before extensions were available. They were dirty hack modifications to the programs. They would introduce all sorts of bugs and since they modified the actual software they were a pain to uninstall. If your cabin in the woods is getting broken into, you won't secure it by putting a lock on the front door. You'll just get robbed and have a broken window. The real problem is users accepting and running installers that install crapware. You effectively give it permission to do anything it wants.