When I objected that, no, the two paths equally lay and that the difference was unimportant or unknowable, my high school English teacher forcefully badgered me back into the common misreading -- and then promptly took the minor glory of explaining the more accurate interpretation to the class for himself! He was smart, had a PhD in lit from UMass Amherst, must have known what I was getting at and in all likelihood consciously blocked me. I felt so cheated and for the first time saw a teacher as a competing ego rather than a helper, and I realized that I'd better learn when to trust myself, even in the face of authority.
About the poem...and yet the choice DOES make all the difference. The paths go to different destinations. The unknowable part is the true message; the 'just the same' part is only in the appearance, which is what makes life uncertain.
Yes, thanks, I agree! In fact I realized a few hours ago that I'd miswritten by including the "difference," but didn't change it and even wondered if someone would comment on it and, yes!, you have. So thanks. As for the poem, I'm no authority here and I wonder how you see it; to me "that has made all the difference" feels intentionally ambiguous, partly ironic or not, able to reflect the reader's view from different angles and distances. But in any case yes I'm completely with you in that the poem's only stable claim is about the apparent sameness of the paths where the traveller makes their choice, a choice without any distinguishing information. I suppose it does raise the question, what is this "difference," to be mentioned after a sigh, and how valuable can it be when arriving at it versus some other destination came down to a coin flip?
Oddly, my advisor (I have a BA in lit) asked the class to comment on the often ignored line -- but then left it when no one offered the more correct interpretation. (Why I didn't bring it up is another story.)
Funny enough, not long ago a friend who attended the Iowa Writers' Workshop (considered the best MFA in writing in the country, if you're not familiar) said, out of the blue, "about that Frost poem" and I replied, "about the same." We both laughed. Apparently that misreading is widespread, even among the most promising new writers.
A further takeaway is to keep a hidden recorder when dealing with these academic authority figures. That way when they stab you in the back like that, you can expose them in front of your class.
Just make sure you have a way out when they give you a failing grade.