It is worrying when the hogs disappear like that, but there could be so many reasons why. It may be that somewhere along their route has been blocked, someone else could be feeding them nearer, etc.
I have been feeding the hogs here for many years. Not all the hogs from last year have reappeared, but that is not a huge surprise as they estimate about 30% don’t make it through hibernation. I suspect that includes hoglets, but even so, not all of them are likely to return. Also, I wonder whether the male hoglets disburse a bit when they grow up. If they stayed in the same area they would be forever being biffed by the bigger boys. Certainly there were more of last year’s hoglets at the beginning of the season than there are now and that seems like a familiar pattern.
Of the adults that did return, there are a couple I haven’t seen for a couple of weeks, including one who had been a regular visitor for at least 2 years. It is difficult, not knowing – but the hogs there may reappear. If you have been accustomed to feeding them, I would keep putting a bit of food out in case they turn up. I always think, with hogs, you can never rely on them to do what you think they are going to!
Good luck. I hope someone turns up again soon.