I read it, also decades (and decades) ago, and barely recall it. If I recall correctly, the theme wasn’t so much different from Mark Twain’s Prince and the Pauper, which is much more memorable to me.
However, I haven’t seen any of the recent references to it in popular culture that you mention. Could you link to any of those, or provide other examples?
On a somewhat related note, I recall how I used to enjoy the film adaptation of Kipling’s Captains Courageous as a boy. I think I may have watched that a half-dozen times. (But the last time I watched any part of it – maybe five or six years ago – I could barely contain my disdain for the obvious schmaltz of the movie. Not that I abjure all schmaltz…)