Well, Elvis may have left the building, but you are still here with us, and still jamming with "much better musicians" (?!?), so obviously that train has NOT left the station ...

Now back to your OP ... A number of years ago a very talented musician friend - he plays multiple instruments - and I started jamming one night a week, playing songs from the 'Real Book' ... soon a guitar player, bass player, and another sax were added ... I was BY FAR the least talented/accomplished musician in the group, which forced me to work on tunes I had never or rarely ever played before ... I got to the point where I could at least lay a good basic chord foundation for them ... unfortunately, various situations eventually brought an end to the sessions ...

Now, my motivation for learning 'new' songs is just my love for music ... of course the songs I am working on are MUCH simpler than those I worked on during the sessions, but there still is a good feeling of accomplishment when a song becomes 'performance worthy' ...

Keep at it, chas ... the 'pain' doesn't last long ...

BTW ... in a recent travel to NY, listening to the Real Jazz station on Sirius radio I heard Charles Earland's version of "More Today Than Yesterday" ... very reminiscent of your version which I have on my iPOD ...