I've noticed that a significant number of modders actually use new updates as an excuse to try out new ideas and refine existing ones. Azanor himself has done this on several occasions, and I believe Thaumcraft has turned out the better for it. I honestly can't play Thaumcraft 4 anymore-- every time I think about going back to it so I can play with all the Thaumcraft addons that haven't updated yet/might not update ever, I lose all enthusiasm upon remembering that I can't make a voidmetal golem with scissorhands and a unicycle for legs. (Not that extensive golem modularity is the only new feature keeping me from indulging in Thaumcraft-related nostalgia, but its lack is definitely the biggest dealbreaker.)
While I'm sure this type of thing would happen without new Minecraft updates, it seems to me that they may reinvigorate the modding community as much as they burden it. It's sort of like how game jams work, I think; interesting games that play with novel concepts happen without them, certainly, but somehow the former have a habit of cropping up more often when the latter are around. Of course, the comparison doesn't totally work, since game jams don't usually cause people to completely burn out and abandon great concepts that we may never be able to replace, but the point is that choosing to stick with one version may have its own downsides. Whether those downsides are worth it is a matter of debate, but one that's definitely worth considering if this sort of talk ever becomes serious.
It would help a lot if the new minecraft updates were more interesting than they usually are, but the vanilla 1.9 update is actually more interesting than the 1.7.10 one was in my opinion, so... at least there's that? In any case, I agree with everyone else's sentiments on this one, Azanor. Your mod is what made me finally take the leap to 1.8.9, and your mod is all I need to keep me happy on 1.8.9 for as long as it takes to see it get even better.