My experience with comcast has been extremely variable depending on where I live, and in particular, what other ISP options I have.
When I lived somewhere where the only alternative was terrible 5mbit (advertised, actually much less) AT&T DSL, they wouldn't extend any of my discounts and even when I canceled they didn't even try to stop me. They basically just told me "haha good luck, you'll be back".
When I've lived in other places where there are options like webpass or fiber, they behaved much more like you're describing.