I don't get where this "Everything must be free+ads' mentality comes from.
Netflix thrived for a decade using subscriptions, Microsoft and Apple's businesses are primarily subscription based.
AIs are so extremely useful to some users, that they'll gladly pay $$ per month to use it. And the size of 'some' increases radically with each leap in AI's capabilities.
GPTs don't have to be gimped to just search. Even GPT-4 today with wolfram alpha can obliterate most low-level tutors. It will be a personal tutor, therapist, coding assistant, secretary, storyteller, entertainer all in one very soon. People will pay for it.