Back to elven trades.
Remember how, when we discussed whether or not Maedhros would have a prosthetic hand, we talked about the elvish aversion to 'machines'? Whereas orcs are very inclined to think in terms of machines.
Men like machines.
I'm fairly certain that's the main reason there's a difference in 'skills acquired' when comparing the Easterlings learning from the orcs vs the Edain learning from the Elves.
Elves are into art. They will of course create the tools to allow them to make their art, but they are at heart artisans, not engineers. Even the Noldor (who are the most engineer-y of the Elves) have a more naturalistic approach to their place in the world than your average Man would. The Elves may be happy to teach the Men various skills, but they will (naturally) teach the way that they do it. Men, who are going to care a lot more about efficiency, will be left to 'adapt' those methods on their own, rather than adopt them wholecloth.
So I agree with those who say the elves aren't very adaptable as teachers - they don't recognize, oh, here is a thing that the Men could do, but they'll need to do it differently to be quicker, simpler, more direct. They are just going to say 'this is how we do this' and let the Men figure out how to adapt it to their own needs.