For the simple reason that a lot of the MV people come from abroad and have other things to do on monday, and so sunday's visitors were greeted by a lot of empty pitches and vehicles moving out. That's why a few years ago it has been decided to start & end the show a day earlier.
That being said I had a great time, stayed the whole week and walked the stalls every day. Around noon I would go back to the camp and sit out the heat for a few hours in the shade, with a drink and a book or just napping and back to the stalls after that. I did notice the already mentioned decline in numbers compared to a few years ago, and I hope this is just a transition period and numbers will go up again.