Because part of the game is time based balance, you are supposed to use your early game advantage to get more resources and inflict MP damage and get 2 tanks to his 1. its not impossible to kill a 15 minute p4.
Part of the game is also bullshit based, like the increasing irrelevancy of cover, blob-warfare, instagib crap across the field, units that shouldn't even exist in this game, idiotic RNG, terrible pathing and awful faction design.