Even the likes of Joe Cornish earns little from his prints - he suplements his income with books, courses etc. I shall lay down a challenge to all UK photographers out there - how many of us have bought a print from a UK photographer? How many of us have anyone else's* photos on the wall? There just doesn't seem to be a market here for photographic images, bar the usual 'famous' global ones.
* I'll exclude any other member of the household in this.