What's the complexity you're referring to? I don't see it.
Having lots of choice for window managers is decades old and completely normal. It's modular and it continues to get easier. I don't see any burden but perhaps I misunderstand.
I were thinking of complexity of patching the software and keeping up with upstream (i.e. maintaining a fork).
I just have a feeling (highly subjective, sorry) that some major GNU/Linux distros (especially Ubuntu) are turning from a distribution of loose coupled exchangeable components to monolithic tightly-integrated products.
Well, Debian seems perfectly fine in this regard, so even as Ubuntu user (for now) I don't care much about the situation. Sorry - I were wrong writing like this was about the whole GNU/Linux ecosystem.
IMHO the complexity gets a bit too high, and cost of maintaining forks gets too big, so even free licensing does not really matter anymore. One has to be very motivated, to keep up with his fork.