I'm pretty sure Pantone would have charged only a fraction of the cost if Adobe would have included a license for everyone.
Since only a fraction of Photoshop users need Pantone, they now need to pay a lot more.
I assume that's what was the case until now. Probably got too expensive to continue.
I think those needing to subscribe to the new Pantone service are more likely to be paying for the full cc suite, not the single app model. This is quite a bit less than that per month.