It's not profitable because it takes the exp of an entire vein of gold or diamond to enchant one item, at level 32. It's set so high that we can't afford to do anymore than maybe sell them at an extremely high price, and who wants to pay 50c for a pick that may or may not be absolute junk.
Secondly, if I want to enchant my own items, I take a huge risk. I lost half of level to get 4 decent picks to use, of which it will yield maybe more exp than I used, but wasted a stack of diamonds to utilize 12 of them as well as having to work for an entire half level back. I liked it the way it was before it was changed, when I could afford to enchant my friend's weapons without having to ask for something in return because of everything I lost doing it.
EDIT: With this new plugin that kills everyone the second we log on, I've lost about 20 diamond picks and 2 levels of exp, as well as a slew of materials I need. Maybe off-topic, but do you listen to your player base? How many of us will it take to tell you that the way things are is wrong and needs to be adjusted? No class has to make the sacrifices we need, yet we get nerfed by requiring even more. We not only sacrifice materials, we sacrifice exp and don't even get a guarantee of what we will get out of it, unlike every other class. And then, to follow up this new anti-exploit login that seems to have failed in proper testing is murdering everyone who logs in, all in the name of preventing one tiny exploit, a problem best solved by banning those who abuse rather than punishing innocent players in what seems to be a measure inspired by laziness. Maybe playing admin is hard, but those who are in a staff position accept the work and thus I doubt going to ban a player who exploited in is going to be so much harder than having coded an entire plugin that screwed up and punished us, instead.