pop 110/995, imap 143/993 ?

[Gedalya]

Bottom line, a server operator's view can be a lot narrower than this, especially in the scenario where you serve the general public and do not control the clients.
There is definitely no reason why you wouldn't want to serve ports 993/995. The MITM thing can be used to argue against serving ports 110/143, and some servers indeed do not offer those.
But you'll always deal with people who would insist 110/143 is the "right" away. It's nice to provide more than option and you can expect many modern clients to default to requiring STARTTLS, and do proper certificate validation. On my own server I provide only 143, and I control all the clients. So you know my taste on the matter :)