Well, during the initial "tech" (broadly interpreted to mean computational processes that somehow involve the internet) revolutions, there were not 100M, nor even 1M users to be gained.
And what is a "user" when it comes to ChatGPT and it's ilk? How does that compare with the definition of a user of, say, the web? Or of SMS ?
With most other technologies before this there was the issue with rollout of physical infrastructure. And that is still true somewhat. All the big AI players want more AI processors and would take possession of as many as they could get.
Buy the other side of physical infrastructure is already here. The internet, cellphones, and computers already exist in mass and can be utilized by AI now. We didn't need to build new highways for this. No new towers. No wires put in the ground. Those fields already exist and are ready for planting.
And what is a "user" when it comes to ChatGPT and it's ilk? How does that compare with the definition of a user of, say, the web? Or of SMS ?