I guess for it to happen it will probably start with something similar with android. It will probably be open source then whatever company owns the brain implant would then start introducing nifty feature which is only available to their service all you need to do is login. That is there then they will lock you in their environment and introduce eventually a microtransaction or a subscription feature probably harmless at first can work without it then gradually it becomes a needed feature without it your device is pretty much useless.