I guess that by the early eighties and nineties, the thought of buying an aircraft just because it was built in your own country was a bit outdated.
McD stuck in traffic LOL.
They were always going to have a tough job IMHO. As we can see, very few companies had a heritage of using DC/McD aircraft. Plus with the benefits of buying "family aircraft" such as the 737-300/400/500 , 757/767 and A320/321 aircrafts, they were never able to get a foothold.
May also have been just for the simple fact that they were not the right aircraft for the airlines that were buying. Too small? Too heavy? Lacking in airfield performance? Who knows.
I do remember reading that there was an MD
-8x operator who had decided to swap for Boeing products because the long wheelbase of the MD8x caused some operational problems due to the large turning circle. Given that 3 of the 4 UK operators were charter carriers, and the state of some of the smaller Greek airports that they would have been used to, this may have been a factor too.