I suppose they could. I just think there's enough driving patterns that can be detected in aggregate, that a network could detect your typical style much better with everyone's data, rather than training just from you.
There must be some training involved on the user level. My route to the freeway can take 1 of 2 parallel roads. The bigger road is theoretically a minute faster but often enough the left turn lane backs up for multiple light cycles. The smaller road is quite consistent in it's timing. A minute slower if the lights work out and a minute faster if you would have to wait.
I prefer the consistent route and now Google almost never tries to send me the "faster" way.
