Could it be done ... definitely!

Will it be done ... depends if some one invests the time to do it!

Even without AI, computers were able to beat chess Grandmasters just by using their sheer processing power. (AI chess programs have since been developed such as AlphaZero)

Chess has very few rules and a "pause button" between rounds which fits in perfectly with simulating future rounds and planning ahead.

Now the real question becomes "How would you use AI to beat human performance in Trackmania?"

You could in theory create an AI that was able to do the runs in real time a supposed SuperPlayer.

Another way would be to train the AI on the layout of each track or at least the desired track, quirky game physics, game mechanics and other factors and have it create a TAS input list.

With AI the goal is to arrive at those answers faster than the brute force method mentioned above and with less energy used.