As Kaktus29 states, the T-80's advantage with those ATGMs is more a function of the terrain than it is the munitions.
The advantage of the 9M119M is drastically amplified in DCSW by the fact that it's targets are usually in wide open terrain with no cover (due to the relatively low-poly terrain mesh of the black sea map). In reality, their targets wouldn't expose themselves for the incredibly long time of flight of 9M119M, especially given that the target knows it's being designated (by way of laser warning receivers).
In realty, the 9M119M (and other semi-active homing missiles) are actually disadvantaged against conventional, unguided, fire and forget tanks shells because the semi-active homing rounds have a long time of flight, and require the firer to remain exposed for the duration. However, this doesn't pan out properly in DCS given the absence of realistic cover. They're only really at an advantage in a situation where both parties have no choice but to remain exposed to each other for the whole engagement. In a scenario where the M1 gets to roll up exposing its turret for a moment, fire is main armament, then reverse behind cover and jockey to another position before popping up and firing again, the 9M119M's advantage disappears. In fact, the munition becomes useless at that point, and the T-80 will be forced to revert to conventional unguided shells.
You can be sure that when Nevada comes out, you're going to see a drastic diminishing of the T-80 /w 9M119M's advantage over M1s. And this will be due to the high-poly terrain mesh offering cover for proper tank engagement drills. The 9M119M is a clear advantage when used on a wide open, 3km^2 empty parking lot, but that's about the only place where it has the advantage.