First the Nutcracker and now Kielder Calling. A couple of years ago the Wild Boar 24 got pulled also. Has the mid sized event had its day?
I don't know - it seems to me that it's mainly multi lap endurance events (6, 12, 24 hour) that will be the most vulnerable. I see this as a pretty mature market, and most of the established events have taken on their own personality and reputation, whether it's for atmosphere, course or even timing in the season.
Obviously an event succeeds or fails on the number of entries it receives..
From a participants point of view they require a pretty big commitment in terms of time (training, and a weekend or so away) and money so there's probably only one or two a season that Joe Average will go to, especially since the courses aren't normally that memorable, unless the weather intervenes.
On the other hand sportive type events (I'm no longer sure of the correct term) such as Dyfi, Honc etc etc can be fun even if you're not fit, or you're hungover, and you just want to ride out with a group of mates, the courses and views are much better and you're not riding round in circles. I think that as the average age of the mountainbiker increases, and there's greater pressure on our time (ie families) then we'll look for better value for our time.
Ten years ago I wouldn't have looked at riding cross- now I know that I can do a season and pretty much be back for a late Sunday lunch after each race- if I want to test my endurance, that's where I'd focus.
A bit of a random ramble, I know, but non technical endurance events don't really do it for me any longer- I'm not sure whether others feel the same way?