Because it didn't involve any service increase for those of us who live on their Euston-Birmingham service, which was busy even before - making it a worse experience for those of us who arrived for the first service, which at rugby back then was LNR 3/4s of the time - great that people were using it, but it should only have been done if there were more service increases.Liverpool - Euston didn't uncouple.
What is wrong with it being a budget Liverpool-London route! It's called suppressed demand, and packed trains are good!
Note that it didn't do Virgin/Avanti passenger numbers any harm.
It was a stupidly thought out idea and, quite frankly, I'm happy that various authorities stepped in and ensured it was ended.