There is competition in my area and I stay on it. Just as a counter anecdote.

There is competition in my area and it is way faster, and I did switch

But the competition isn't great either, so I get why people don't.

The modem/router the other company uses (can't use my own modem) is terrible and their support had no idea what I was talking about when I pointed to the DHCP table full of random shit that it wasn't freeing up, and logs full of DNS errors. And the wifi access points they provided were terrible too (free, but terrible). Eventually I worked around that by just adding my own router in the mix with a (internal 192.168) static IP, cut their DNS out of my router's list of DNS, and used my own wifi access points (which I had from Comcast days).

After my third support call I got a tech who provided instructions on putting their router/modem combo into bridge mode, but I'm hesitant to actually go through with that because I have no confidence their support can unwind me if anything goes wrong.

Like sibling points out, Comcast does offer faster download speed due to the competition. Still not as fast, but w/e.

The service you receive is made better just by the presence of competition.