One possibility is that all the players who thought that they might enter didn't bother because thay thought that nobody would enter
Tournaments require a critical mass thing to get them running, once you have a core of entries getting a few more seems a lot easier.
It does seem though that in the UK a lot of tournament ancients players are either staying with DBM or switching to Field of Glory.
On the plus side the DBMM tournament at the BHGS Challenge next weekend is 66% larger than last year, perhaps the players there can form the core required to get DBMM tournaments rolling in the UK.
