I think this is true. If you wanted to do max difficulty reliably at say level 25, you'd need both a full team and a fair amount of support, along with a scattering of IO bonuses throughout the team. And you'd still need to keep on your toes.
And this sort of balance feels more like the dynamic in other MMOs, as a general threat per encounter level.
But for some reason people at least judging by some very vocal status quo defenders around here, do not want this dynamic to continue up into the endgame. I'd argue that not even a hint of this dynamic exists by the time you have a "fully done" build and incarnates at T3+ playing such content as ITF, etc. No wonder Support feels left out.