This is not an actual fact or anything – but the impression I have is that BC collectively see Enduro as “Downhill with no protective equipment, no paramedics and only 3 marshals per track” and after the sad death of a spectator at a DH race last year (and a road motor rally in Scotland) it was all just a risk too far for them.
It would be hopeless trying to run an Enduro like 5 DH races in a row.
Things will settle down, loads of organisers have been running Enduro sans BC since the start (Tweedlove, half the SES rounds last year) so it isn’t impossible.
Landowners will be adding to the risk aversion too, FCS being a likely contender on that front.
(all my opinion of course – I am retired from event organising now so can say what I like !)