The show at the NEC sells out every year and there is a waiting list to get in (as an exhibitor) its also getting bigger each year, so if you compare that to Redbridge, that is no longer running, I think you'll find that the high cost is justified in terms of the footfall of trade and retail customers.the consequence of that policy is reduced participation due to high cost.
Contrast this show with Redbridge where anyone could come and show their wares for free. If you like the spirit of Redbridge, perhaps you should encourage traders on this forum to band together to take this format outside London.
There were a lot of high profile buyers at the show this year.