From what I see on the online groups the 90-95% capacity seems to be mainly made up of it's cult like followers. There are a few very hardcore fans who visit multiple times a year and won't listen to any criticism at all about it. It is very much riding on the coat tails of memories and childhood feelings.
It's a holiday for people who are outsidey, they don't mind a walk as long as it's flat/ on a clear path and there is a coffee shop or a pub at the end of it. They want to be able to walk in their trainers/ flat shoes/ sandals. They want to be able to sleep in the indoors with home comforts. It suits those who like to go on holiday to a resort and want to feel "closer to nature" without having to rough it in the woods in a tent with camping gear. It very much has it's place.
The problem with CP is that it has no like for like rival. There are a couple of Haven's that offer the swimming side of things and manufactured nature. Butlins offers the resort experience but is very run down and has a reputation for a certain clientele.
This has led to complacency. A few of the CP sites have become very run down, with damp, poorly maintained lodges. Sites have expanded but the facilities have not been expanded or had any proper investment. It's year round opening means that there is no proper annual maintenance of everything, instead maintenance is done around guests with parts closed off. CP has always been expensive but nowadays it feels poor value for money. Restaurants are chains and food served is mediocre. Services such as regular housekeeping during your stay have been withdrawn, they have removed the small complimentary toiletries, check in at the basic lodges is later, swimming hours are reduced, some sites are plagued by short staff and restaurant availability/ swimming flumes and slides and activities are reduced.
For the prices charged (especially in school holidays) people can go abroad for cheaper and almost guaranteed weather. Even if staying in the UK for the price of a basic lodge you can get a much higher standard of accommodation elsewhere. For example we tried to get a term time weekend at CP in April 2 bed basic lodge and it was £699. For £500 We got a 2025 caravan lodge on a holiday park with dishwasher, washing machine and tumble dryer, fridge freezer, air fryer, hot tub, coffee machine, access to the swimming pool and onsite facilities and daytime and evening entertainment.