" 3 Healers holding Gen all match."
3 healers at the gen can easily be countered with 7 players just taking generator and then your team leaves behind 3 healers. And you can even handle this with less people if the enemy healers aren't all attacking different people all the time.
My last game there was a healer and a paladin guarding middle. We took it over with just 4 people. 1 DPS was damaging them so the healer had to stop attacking us to heal themselves up. The 2 others and me were all interacting with the generator. Once we took control of middle, we just left behind some healers.
"5 Healers pushing back an entire lane then standing outside of cannon range picking off anyone going out."
If you had a group of people dying to 5 healers, I'm afraid to say your team was just bad. It's not that hard to just run away from them if you need to be somewhere else. There are many ways to get out of a base. Also if you do get into combat with them, it takes 1 healer to undo the damage those 5 healers are slowly doing on you.
" Emptying TP+popping Enliven and running out of TP AGAIN without even scratching a SCH. I then die to Broil spam."
Why did you die? So after 10 seconds, you saw you had 70-80% HP and the enemy SCH had 100%. Then after 20 seconds, you probably saw you had 40-60% HP and the SCH still had 100%. Then after 30 seconds you probably saw you had 10-30% HP, the SCH still had 100%. But you still stood around trying to fight? For what reason? Wasn't there anything else you could be doing instead of fighting a pointless fight for over 30 seconds?
" They also laugh in the face of all mechs."
And mechs laugh in the face of their damage. I main AST in Rival Wings now. I've DPSed down different mechs for minutes without dying and I hardly do any damage. And a lot of the damage I do to mechs can be made negligible if someone was protecting the mechs. Like if there was a DPS with the mech which would force me to stop DPSing the mech and heal myself every now and then from the damage they do.
"The issue isn't damage, it's how unbelievably futile it attacking a single one of them without having someone with stuns."
Then why keep trying to fight them? You know it's futile. Depending on the context, just ignore them. If it's in the context where you shouldn't be ignoring them, then you should have enough man power to beat them to help you.
And the progress the 5 healers are making against the 5 DPS can be made 0 with just 1 healer. You could even change up the situation I said and make it 2 DPS and 1 healer vs 5 healers. It's still a stalemate. But the enemy has to put in more players into this drawn out fight.
Edit:
To be honest, if your 5 DPS couldn't kill 1 healer. Then some if not all of the DPS involved were really bad.