I would think too, but not all breeders have the time (or supplies) to make F/T. Imagine thawing 500 different size rats and mice.Then (if needed) do the zombie dance to 500(not to mention a FULL Deep freeze of rodents, probably more than one because 500 rodents a week takes alot of room.) snakes.
There goes the weekends...lol. Im sure some breeders do it, and don't mind it, I hope I will be able to feed live, so I don't have to deal with the frozen rodents. Yay for food variations!