Also, a lot of times there is a difference between "behind" and "no chance of winning." While I admit, a comeback from the enemy being godlike is unlikely unless his teammates were shit (after all, godlike is... a dozen kills? That's, at minimum, assuming they were somehow all on you at level one, 7200 gold and a ton of EXP, with a reasonable amount for that [with your level at 7] being 10k.), sometimes you can be down a bit but not lose. EX: One time I was playing with an Oak and I was UB. They were TB and a Tower Rook.
Well, I knew we didn't have any shot at getting much early advantage (Tower Rook is hard to beat at low levels, and TB just farms faster than everybody else), but we just avoided being killed, got down in Warscore, but eventually hit the levels and gear to where TB could barely do anything and their Rook (who had actually been smart and teched into hammer smash + boulder roll instead of going pure towers like a lot of people do) just couldn't take both of us at once while we kept TB constantly going back to the health crystal.
However, what if that situation were reversed? What if, through some absurd amount of skill, masterful planning, or by using a buy/sell trick to allow UB to get his basic gear, but give something to Oak to sell so he could buy a wand of speed instantly and gank people early on (that's probably unlikely, but it's possible and it's a good example.) Or maybe the TB and Rook just played like crap. Well, either way, their team is at a disadvantage during the prime levels they should have an advantage (or for TB, during any stage when he can get enough EXP from creeps to keep his level advantage despite the fact that creeps give him the same EXP.) So that is hard to comeback from; you can't outgear an enemy who can push better than you (without flag locking the enemy gold flag or the enemy getting priests). You also can't wait until you hit levels where you have an advantage, because you are already at your advantage. Therefore, you are dead.
I also think that it is impossible to make a comeback with a horrible teammate (definitely in 2v2s, and almost impossible in 3v3s). When I say horrible, I don't mean "overextends himself a bit and has a bad build" though those certainly are bad traits that can hurt a team. I mean "goes into obviously suicidal battles, doesn't run, does not stick with teammates, and has some kind of belief that getting off two autoattacks on the citadel is worth getting killed [teams of all Last Stand Oaks group suiciding at the enemy Citadel with Soul Power in full effect to take it down instantly notwithstanding.] Basically, if you have a really bad teammate, unless you can tell your opponents are bad, you've lost. Frequently, I quit matches (with a GG and "sorry for the 30 seconds of lag") when my teammate acts like this; there's no way I'm going to win with a Sedna that went healing aura/yetis and charges at the citadel every time she respawns.
So in summary: If you can level into an advantage, you can make a comeback. If you can backdoor easily [not a bad thing, although it unfairly favors Erebus] or hold a choke on big monsters [bad; even giants are a bad idea against a decent team with AoE on Crucible], you can make a comback. If you can't level into a comeback, it's probably over. If your teammate is horribly suicidal and essentially makes it a 2 vs 3 nightmare demigods, you aren't going to win.
Also, on the game with the big comeback; you guys probably hit your ideal level range. The thing is, all of your characters (besides TB) hit their ideal peak at about level 15 (well, 10 if it was an Ooze UB, but that coincides well with a mines Erebus as well, so if you went Ooze UB, mines Erebus,and a combo TB, you were very close to a really big advantage.) The other team... not so much. QoT really peaks at... level 1, when she is invulnerable with shield. She can be good if played well, and certainly should almost never die, but it's really hard to push with her in anything but 1v1 games because she just can't kill anybody. If she didn't have shield, she has no really useful trait. Regulus peaks at either 10 (mines) 15 (snipe, which I presume is what he was doing to get so many kills. Though he is really strong past 10 no matter what, and at 10 he gets his biggest snipe, so that is arguably his peak) or... I'm not sure where for AA builds. Erebus hits his peak at 10.
So basically, the enemy had a bad QoT that was way away from her peak levle area, while you were about to get to a point where all of your demigods were at their (skill based) best, while the enemy at best had just Erebus and Regulus synergizing, which wouldn't match the power of three. Not only that, but your team had up to two stunners (UB and Erebus) and up to three slowers (Regulus with mines/main, TB's ice rain, and UB's diseased claw), which synergizes incredibly well; with a regulus laying mines down while UB charges in and grasps and TB starts his ice combo and ice nova's right as TB finishes his stun, you've essentially chainstunned the enemy for a huge amount of slowing and about 6k damage, which is simply absurd. Even in a 3v3 with the enemy outgearing you, they just don't have the kind of chainstun ganking ability your team has, and having a shit QoT who wouldn't shield them (which would mitigate the damage immensly) just made things worse.
