From what I remember, his reasons for living in the cabin are only explained at the end of the book. I wonder if people forget or are unaware of his intentions and just remember the 'dropping out of society' part.

my memory doesn't recall much beyond his long stretches of describing nature there...

but the point is: maybe going off-grid can be relevant? changes also can also occur in "small bubbles of reality" and their impact can be extensive or narrow, still, they are a change..?

...and then he came back and spread his contributions to the society, notable figures inclusive. Had he stayed in that cabin and only wrote in his diary, we'd had no idea a Thoreau ever lived. So this was not an example.