> Am I missing something in my assessment?

Something you may be missing is that these models are being made available to collect data from users to make them better. Is data valuable to competitors commonly shared by competitors?

Also ever peek at charts showing how GPU power is growing vs time? In perhaps a decade our pocket devices may be locally running the current models. Anything done now will not help in the long run. I expect the various efforts to detect AI writing and AI art will add up to nothing because the error rates will be too high to be useful.