At the risk of turning this into a PhD thesis, my guess is that the thousands of sportive riders that are out (and it is thousands) are often from out of the area and this is just another facet of the area's outdoor tourism. Such people probably want a professional level of organisation and support and are tuned in to the sportive 'circuit'. I think that triathalon is big around here too and that tri riders would be keen on doing 50 - 100k but not so much the longer stuff.
A lot of audax riding, almost by definition, is unsupported - there's the routesheet, off you go boys! - and that is not the product that floats their boat. Those who were on the A Corless ride on the same day as the 3 Peaks ride before Christmas, saw a very clear demo of that as we rode past their start.
I am not involved with club cycling, but I suspect that they are quite happy with club runs and time trialling, plus forays into cyclo-cross and MTB rides. Add to that the sparse population compared to central Lancs/Merseyside/G Manchester etc etc and you can see why it is a bit of a backwater.
Again, I'll reiterate an earlier comment - 'there is no them, only us'. Hence my indications that I will put a few things together, but it will take a bit of time. No point in rushing something out for 2013 without careful preparation of route/control choices. However, when ready, with some well targetted publicity, I am sure that the fantastic resource we have will attract a good field from within AUK, from local riders and the outdoor/sporty tourist fraternity - as long as they accept the different challenge and nature of an audax ride - there's the routesheet boys, off you go and don't be looking out for those tent things with no sides every 20 miles with a load of chaps dispensing gels, powders and tablets!
Ever onwards!