I know what you mean by "let them teach you about their field", but I think the point of the whole discussion above was that you cannot design a very good product unless you use it yourself. I dont remember who said that in the first place, but I remember such things as "men can't really design stuff for women, because they don't really understand how they think". I am not sure if it applies to everything but there is some truth in that. In software, you can see a similar trend: Facebook is a good social tool because the funder actively uses it all the time. The iPhone is a decent phone because the CEO was going to be an active user. I have heard tons of stories from friends/coworkers where design decisions are taken by non-users, and they usually fail miserably once on the market.

I agree with you that spending a lot of time with others who are not like you is definitely an improvement, but it is still not going to be as good as if they were able to do something on their own.