Shouldn't the AI in DE do other strategies instead of just rushing?

Hey guys, I've been playing a lot of DE recently, mostly for the US Challenges and to train other civs (I used to play Russians almost exclusively)

Doing these challenges/training, I noticed that the AI seems to ALWAYS rush -> lose steam -> lose game. Its almost a formula, doesn't matter what civ they get (I leave it at random), they will always rush rush rush then suddenly lose steam by Fortress and proceed to lose the game. Isn't that a problem? AoE2:DE suffers from the exact same issue I feel, the AI never changes its strategy and becomes so formulaic that I think you can't reliably train strategies against them.

I play on Hard, Hardest and Extreme depending on my familiarity with the civ (with Native/Asian civs I play Moderate because I suck with them)