> Wouldn't this violate the "encapsulation" pillar of OOP? As far as I know, it's always taught with encapsulation, inheritance, polymorphism being its three pillars.

Encapsulation is "if you have a state, you should encapsulate it". It does not ask you to have a state (even less a mutable one). I quite often use object to represent a logical piece of code, without any attributes.

> I'm not sure functional programming has lost yet. I haven't worked with it personally, and so can't speak to its merits or demerits, but have heard a lot of buzz around it recently.

As much as i really enjoy FP, I don't think it has more than 1% of the market share of software engineering. And I've been hearing the "heard a lot of buzz around it recently" for more than 10 years.