I wonder if many ISPs have been delivering such bad service for so long that some people don't bother to ask their ISP for help any more, even if it is an ISP that is willing and able to get things fixed.
A kind of general lowering of expectations.
I think there is a lot of truth in that. Some of the larger ISP's have been continually eroding the "broadband product" in almost every respect. From Traffic Shaping/Port throttling on the delivery side of the product to outsourced overseas call centres with very limited expertise on the other.
I'm with Zen at present and been with Idnet in the recent past and although i pay more than the mainstream equivalent (ie large ISP) a recent reminder when listening to a mate of mine communicating (well trying to) with Pipex/Homecall reminded me of when I was with talktalk. He was so glad that he eventually got a solution after hours of tring to obtain JUST his username and password (his only reason for the call) that the thought of going through anything like that again put him off in trying to migrate elsewhere in the
fear of the agro he'd likely have to go through again.
So yes, I think many just put up with bad service and support as they know that they will need to allocate hours of their time to 1) actually get through to the right department, likely after being on hold 2) get someone who can actually fix the problem when they do find the right department.