You would have been right if ML would be as accessible as your hypothetical "utility service" implies. It is not, and getting farther from it.
If you compare ML to electricity, we're still in the stages where a few players have found that electrifying their manufacturing plants makes sense. Small players can't afford he investment in machinery and skills. Maybe when the machinery is hidden behind a "utility" provider (which would also bring down the skill level) they will.
I would say training a CNN from scratch or even fine-tuning one takes a lot of domain knowledge and best practices which often are not standardised yet. Besides, we don't even know why they generalise in the first place! See: https://arxiv.org/abs/1611.03530, https://arxiv.org/abs/1711.11561
If you compare ML to electricity, we're still in the stages where a few players have found that electrifying their manufacturing plants makes sense. Small players can't afford he investment in machinery and skills. Maybe when the machinery is hidden behind a "utility" provider (which would also bring down the skill level) they will.