I wonder if it's just a coincidence that Classics 3.0 is called "Generations" But anyway, it sounds like some people in this thread are confusing "Generation" with "Universe".
There aren't really generations anymore. Just different continuities. A generation suggests something existing within the same universe concurrently. I don't really see the need in slotting different series into different numbered Generations myself. The only reason Generation 1 is called such because there was Generation 2. If G2 had been called something else, "Generation" wouldn't even be used in the TF fandom lexicon.
I called by the generations with fan terms. G1=Generation Alpha G2=Generation Beta G3/BW=Generation Beast G4/RID=Generation Legacy G5/UT=Generation Unicron G6/Movie=Generation Legend G7/Animated=Generation Duty G8/Prime=Generation Tribute