UJM:
They didn’t just “disagree with him” as in “eilu viEilu”. They condemned him for his “innovations” and the like.
Rav Aharon Kotler stated that Rabbi Dr. Soloveichik was responsible for “all the tuma in America”.
As to the main point you were trying to make, had he created “Modern Orthodoxy” as a temporary kiruv stage, then that would have been bad enough.
But, instead, he claimed (when creating MO) that only his (Maskilic) way would survive, and “separatist orthodoxy” would become a museum-piece. Of course, netzach Yisrael lo yishaker, as we just read, so his prediction would obviously not be possible, but that is even more obvious in hindsight.
B”H, the opposite has happened (compare the numbers in BMG and other yeshivos versus those in YU, and also note all the “flip-outs” who realize that “Modern Orthodoxy” is absurd, and then go to NIRC or other such yeshivos after being shmaded in YU, and become traditionally orthodox instead of “Modern Orthodox”). BE”H, this will continue to happen until the heresy and idolatry of “Modern Orthodoxy” finally becomes history.