I have no idea how long this upholstered bed trend is going to last. It's been around a while now and is quite strong- of course there have always been upholstered headboards- I happen to find them off-putting for the reasons you mention. I have seen some where the headboard appears to be slip covered. That would be better for me. You can still find non-upholstered beds, and ones upholstered in leather.

We have a dark grey, almost black upholstered headboard. We can definitely see dust buildup if I don’t clean it regularly (weekly, when I dust the rest of the room). But wood and iron beds I’ve had in the past also needed dusting. We have not had a problem with dirt accumulating from heads touching it - I think neither one of our heads touches the fabric. I do have it professionally cleaned once yearly when we have our carpets cleaned.

I have no idea if they’ll be out of style any time soon, and I don’t really care, to tell you the truth. I’ll use our bed for as long as I like the look, in style or not.