Conclusion

You can discuss whether you consider the current playerbase worldwide at this very moment is active or not. There is clearly plenty of activity with open lobbies and welcoming people to play with. If you count all lobbies together, you get a fair number.

What people have troubles with, from my point of view, is a cultural and technical understanding of how the multiplayer works. It starts with the highly questionable, not understandable region lock to begin with, and continues with the freaking weirdo bug which gives defective results when searching for a fitting lobby.

Take as example my French search:
When looking for the same language, it makes sense that only lobbies are shown with the same language. But when changing to ANY language, why are all of sudden the lobbies with the same language are hidden? It is because it is defective - presumably.

My thinking tells me, it actually is not working how it is supposed to be, and instead pairs you with people with the same setting you have.

As in:
You have your game set to English and seach for ANY language, you get only other players which have set their game to ANY language as well. Excluding the player pool who eventually have the SAME language as you. And vice versa. Most visible it became by comparing Traditional Chinese with the Simplified Chinese.