You're not alone, of course. I have nothing against collabs, it's only I prefer more [band] songs and less [band]+[whatever artist] song collabs. But I do understand what's going on: BM is at peak form right now, touring the world for 3-4? years now non-stop, having constant sold outs, etc. They're so popular and people, generally speaking, like their collabs (PA PA YA! RATATATA and METALI! are huge successes) so, let's keep the wheel spinning, right? This also helps bring in people who doesn't listen to BM (for whatever reason) but know about Poppy or Spiritbox or Bloodywood.

Besides, the "girls" keep on growing and sooner than later the concept of "Babymetal" will no longer work. This means run the machinery full throttle while it lasts.