The nice thing about the out-of-copyright classics is that we CAN all contribute to producing properly-proofed versions for other people to enjoy, as people do here at MR. But the amount of effort shouldn't be underestimated. I typically spent 1-1.5h a day proof-reading the ebooks I create, and can do about 20 books a year that way. If more people were to get involved in the creation of properly-proofed books, there'd be a lot more around. I'd encourage everyone to get involved in such activities. Everybody benefits (and it's fun to do
).
So no, I've no inherent problem with this. If you're doing this stuff commercially, and it's a specialist market, the price has to reflect the amount of effort involved.