I've analyzed, theorized, contemplated, and thunk about it over and over.
Throw away the arguments about
- Alien regeneration and evolution any where on the map
- Humans limited ammo and regeneration
- Alien lack of base dependence
- Humans base dependence
- Humans needing coordination
- Aliens not needed as much coordination
At the end of the day, the human team does not have an answer for 5 tyrants sitting out of their base.
1 tyrant is 400 hitpoints and 200 Damage per Second (roughly).
5 tyrants is 2000 hitpoints and 1000 DPS.
Only 2 human weapons can dump out enough DPS to even compare to tyrants. The painsaw and lucifer cannon can theoritically kill tyrants but we all know the drawbacks of those weapons.
The pulse rifle, flamer, and chaingun can be good but it is a matter of time when killing tyrants. The pulse rifle takes 4.4 seconds to kill a tyrant, the flamer takes 4 seconds even, and the chaingun takes 5.3 seconds. In the window of time, a tyrant can deal at least 800 damage before they die.
Of course people will say, what about having 2 humans attack at once. Well, what about having 2 tyrants attacking at once. Its a loss for the humans. Once aliens get positioned comfortably outside the human base, its damn near impossible to reverse it. Sure, you can chase them away, but they just spread out and kill a human somewhere else on the map. They can reestablish their position quickly.