Man, DMST doesn't belong in that category at all. They sound completely different from EitS or TWDY (two bands that do belong in the same category). I never got why people reference DMST when talking about those bands. Is it because they have kinda long songs with lots of guitars and no words? The similarities between them and most bands that belong in the post-rock cannon are superficial at best, I'd say.
Apart from that, I kind of agree with you. The big names in post-rock were total gateway bands for me. I rarely listen to EitS these days, or TWDY, or September Malevolence, or...well the list goes on and on. I absolutely loved them for a long time but they've all become a bit too derivative and self-referential for me to truly enjoy these days. These bands all put on killer shows that I still go to every chance I get but listening to them on my stereo I can't help but feel I've played them out a bit. Not that I'm not looking forward to the new EitS album but I'm not buying that fancy vinyl package and, for me, that's saying something.