I believe there is a general lack of trust in main dealers. My wife’s old uni friend ‘uup north’ had a turbo problem, she took her little VW to the main dealer she bought the car from and was quoted £2,200 to sort it with a unspecified wait for parts, (seriously, she was told they had no idea what day/week/month the parts would be available from VW, they would just give her a call when the parts came in) I got involved and did some online digging (she is single and has little idea about car repairs) and I found her a well regarded garage pretty local to where she lives and they sorted the whole thing in two days for her at a cost of £780 and this local garage is where she will be taking her business in future.
Main dealers bleat about their overheads but when they give bloated quotes, indifferent customer service and are charging up to £150 per hour for mechanics who are often NOT specialists they can hardly expect much in the way of sympathy and/or loyalty from motorists.