The reason you can't replicate the tactics of your enemies is because your enemy literally isn't you. You have completely different problems, strategies, objectives, logistics, and weapons.

It's like saying, "How does the Taliban expect to win in Afghanistan if it won't deploy fixed-win air-support during their offensives?!!" It's because they can't, and trying to get air-support with no capability of preforming maintenance isn't worth it. So they develop different strategies.

For example, try this:

Play a game of chess, but literally only match your opponent's move for move.

You will lose 100% of the time, because your actions are predictable, and the moment you are placed in check, you won't be able to counter your opponent's strategy from that point on.