Why map rotation in Player Vs AI?

Hey. My 4 friends and I love playing coop in this game against bots, but it becomes unbearably stale after a few sessions because we are limited to only five or so maps.

I don’t understand why these constraints exist in an exclusively PvE setting. Is this not an issue other people have encountered?

I am encountering it as well

And based on what I have observed this is intended as the maps tend to change to another fixed small rotation right after most updates

Personally I do not mind it too much as it allows me to memorize the pattern and pick heroes along with choosing strategies accordingly