Again, you're objectively wrong. I have an objective base. You don't. You're basing your opinion purely on anecdotal experience while simultaneously making the argument that groups can compensate for the problem. Yet it somehow isn't occurring to you that your group has somehow compensated for the problem. As I pointed out was possible. So you've seen a couple of trees, to use your analogy, and you think that is the forest. It ain't. Especially since you're defining the game being "broken" as "non-functional" (which is absurd, since any game system will be houseruled into functionality if needed) instead of "Hey, these things are actively bad in that they destroy the designed intent of the game's pacing, mechanics, and character power levels."
"Grind" is easily definable, actually. More then two standard deviations outside of the expected average encounter length, calculatable by party size and E level. Done. Again, math. Done extensively. Your personal experience is... well, not enough to justify the belief you have. So you're just ignorant. Which is OK actually, it is just a game and there isn't any particular reason to put the effort into understanding it if that isn't interesting to you. But if you don't put the effort into understanding it, you shouldn't complain about your opinion not being valid in any objective sense.
Again, you totally misunderstand a very simple fact: this is a game enjoyed by millions by people who aren't you as well as you. Just like when people on this forum give a character concept and ask for build advice and you stear off the rails directly the CharOp stuff every time basically saying they're having badwrongfun if they don't do it your way.
As for compensating, the group hasn't compensated, WotC has for people who don't/can't/want more. The game worked before the feats, they came later.
As for grind, again, you are simply wrong for anyone but you. I've been in four-hour battles that were a dynamic blast to play and 30-minute, two-round battles that were dull as Hades. As an example, we experimented in one group with lowering monster HPs and upping their damage last week. At least one person enjoyed it, I did not. It was basically "pick the two, possibly three powers you want to use this encounter and cue them up, line up and roll". There was no ebb & flow it was just "*smack, smack, smack, slice* two characters were bloodied and we won".
Some people may enjoy that type of game, and D&D supports them also, but not everyone does. The biggest factor in "grind" to many has absolutely NOTHING to do with math, it's the DM. D&D is (now) a very dynamic game but can be enjoyed by those who may not take advantage of all of its features. You can't quantify everyone's feeling with an equation.