Roger, in addition to answering your question above, I'll say that all of the schools that I looked at told me the same thing, they taught traditional B&W wet work, as well as alternative techniques like collodion and tintype and even carbon printing, but they all said the same thing about color "about 2-3 years ago we decided that teaching color wet printing was just not worth it to our students, the fact is any job they might get even for their own businesses would be better served by scanning" the professor even said scanning is better than printing for color because of the difficulty in printing color properly and they completely removed the color labs and equipment because they feel there's no benefit, and all teach scanning techniques for color. They don't even teach how to develop color film, they now have a send out service.
So the cost involved in paying for C-41 that would end up being B&W anyway seems to offset the hassle of dust in a scan. I would never buy XP2 in sheet film, it would cost too much, with little benefit gained, I may use it for transparencies, but really no one is projecting in terms of for financial gain, it's all about the print, I use E-6 for the colors over C-41, but C-41 that's B&W anyway seems futile at the prices it would cost in sheet film AND the cost of having it lab processed....
I'm not saying it's a bad film, it's amazing, but I think that Simon(ilford) understand it's more of a niche product and not enough volume would be sold in sheet.
PS I never ever use ICE to remove dust, it does something to then sharpness and sort of fuzzes the grain, it's subtle but a side by side you can see, so I don't when see the benefit of ICE being worth it for C-41 scanning.