Because introductory CS enrollment has ballooned so much recently, many professors for large introductory CS classes nowadays are full-time lecturers that do not conduct any research. Many full-time research faculty only teach smaller, upper-level classes.

In my experience, this works out pretty well since many of the full-time lecturers do dedicate a lot of their time to teaching (55 hours is totally believable depending on teaching load) and do a really good job of it.