Hence you need people like me to stop you from making the mistake which is entering into contracts with BT Retail that you'll later come to regret.
You are no doubt correct that BT in general is an appalling entity to deal with most of us do not have that experience much like Ryanair supply, to most people, exactly what it says on the tin despite those of us prepared to pay for quality in air travel not touching them with a bargepole!
I was with Nildram way back in ADSL infancy. Slightly dearer than others but reliable and great customer service. Roll forward several takeovers and I was a customer of Opal (part of TalkTalk) and after several months of tearing from my head what little hair I had left I gave up and moved to BT.
BT Infinity has been rock solid and reliable at reasonable cost. I would suggest that probably 95% of BT customers have no complaint because the service works. Should my service go wrong I appreciate I will be dealing with a chaotic and dysfunctional 'customer service' call centre and often poorly trained engineers.
You clearly know your subject and no doubt set very high standards, as I do in anything I am involved in. Sadly the world is not generally built that way. People want cheap, organisations like BT work on numbers. 95% of customers happy, 5% mighty pissed off = profits and success, screw the dissatisfied.
B & Q, Sky, Ryanair, BT all very successful organisations in terms of profit and market share but are they companies I like and am happy to deal with..........
Don't get me started on Vodafone.