You're right that it's hard to get others to learn from feedback if they don't actively work at it. You can make your feedback easier to understand and more action-oriented. But if they're lazy or even just focused differently, your feedback to them won't be very effective.
As a manager, I think it's still worthwhile to give as much feedback as I can. Some of it might be heard and acted on, which will help the receiver grow.
http://yosefk.com/blog/people-can-read-their-managers-mind.h...
Probably better than "Thanks for the Feedback" by Sheila Heen.
But that doesn't mean that you as an individual can't get value from the feedback you receive. You just have to process it intentionally, instead of taking it at face value. That's one of my favorite points in Thanks for the Feedback.
From the feedback that i have got from this thread, however, feedback is a very personal thing and users who really want to improve themselves don't have a solution right now where they can privately request their coworkers(former or present) for this information and not get potentially penalized for it (if negative) by their existing managers in the performance review meetings.
So i think somehow feedback has to be actionable and gives a plan of action to user in such a manner that he effortlessly tries to improve those things in his daily routine be it reading related articles or what. But users generally tend to be lazy which is why feedback in the end seems to be useless for them.