Should the inference be:

FP doesn't scale?

- or -

FP inherently creates small code bases?

Well, having worked on both, I was able to tell that you only worked on one since your stated opinion would likely be very different had you worked with both, so take from that what you may

> Weird how many large OOP codebases there are to find oneself working on and how few large FP ones.

How on earth is that weird when OOP is a hundred times more popular than FP?

The point is to ask why OOP is a hundred times more popular if, according to FP advocates, it's so much worse as a paradigm.

Inertia is a powerful thing. Look at how many people still use C and C++ (and Java!) despite there being arguably better alternatives.