We are a minority within a minority
Just playing aoe2 in 2023 is a niche hobby.
On top of that those who only play single player account for the vast majority of us.
What can we do to encourage more singleplayer folks to join MP?
What can the devs do to encourage online play?
Incentive-wise online play tends to be the bigger cash cow for game devs. Look at GTA V for example.