> So yeah, before I start to rage incoherently, I'll just stop here.
Too late. :-D
Yes, there are alternative to autotools. Normally they are prettier, but less complete. If I have to take some code multiplatform nowadays, I normally go with CMake... but sometimes autotools is necessary, depending on how much multiplatform you want to go (you know, QNX is still a thing out there!).
And, moreover, if someone already autotooled a project (like firefox!), you have to do a lot of work to convert it to CMake (or other thing of your preference). It is janitorial, unglamourous work (so volunteers normally don't want to do it) and it takes some code that does X and transforms it in some other code that does X+0 (so managers won't let you do it, because they want work that makes code go from X to X+Y, preferably for a large positive value of Y).