As mentioned, I've never done a thru-hike, but I "think" I can understand what you mean re. "lifestyle" and "getting in tune with [an altogether different] environment". I would appreciate your feedback to see if our perceptions have any commonality...
I went on a 7-month, solo RTW trip back in 2008. Prior to that, I have done many month-long trips. And initially, I figured the RTW would be a fairly similar experience -- just longer. But a completely unexpected discovery from my RTW trip was the sensation of being completely at ease with wherever I was at any moment or place -- my home (with all the feelings of belonging that one associates with one's home) -- was simply wherever I happen to be!! The "lifestyle" of changing hostels every 1-3 days, of quickly learning and getting comfortable with new locations and street names and cultures, etc. and then moving on and repeating again, etc. -- all became merely "the new normal"! This was much more than just feeling at ease. It was a "higher feeling" of actually belonging to a much bigger world (and also feeling I belong to whatever specific locality of the moment). It was both very macro and very micro at the same time.
I wonder if you felt the same when you wrote "lifestyle" and "environment" up above? That on a shorter trip, you might think about home or even doing post-trip scheduling... and then after a few months on a long trip, home is simply wherever you are at that moment -- until you feel so completely at ease that the entire new environment becomes your home! Towards the end of my trip, I was thinking to myself that if my shipping company had called to cancel my voyage home... I really wouldn't / couldn't care less! I was 100% ready to go home... and also 100% ready to continue on -- in other words, it made no difference at all where I was and where I would or should be heading to next -- it was all good.
Obviously a trip entailing trains, planes and ships is "different" from one where your only transportation is your own two legs. But then, do differences in transportation modes really affect one's psyche from a thru hike or thru trip? I would say "no" -- not much different than trips using different gear pieces!
Are your experience / feelings similar?