Fair enough.
iTunes got away with selling music encoded in lossy audio codecs as well. This and the video aspects outlined above were in regard to the higher quality you mentioned not seeing in porn available legally.
So for the porn crowd file sizes tend to get quite huge if it's good HD material they want; if they don't get this quality legally and want their downloads to hopefully max out the downsream of their connection, they can just as easily purchase a premium account from their file hosting site of choice. I'm unsure about usenet access as an alternative, but it should also point in roughly the same direction.
Porn producers should do what they can to compete with free content, content of superior quality or partially free content of superior quality they won't make any money on if they want to change things. This isn't done right without various considerations beforehand and probably out of reach for small porn businesses which seem to employ underqualified people for their affairs just because they know them or whatever.