Time is an issue for many of us. Because of time, I generally won't learn a new song for it, because what time I do have to play is spent improving those I do know, or as lately, trying to get my hole grail of songs, the Perrodin Two step.
Another thing for me, and maybe some others, most of the last few songs are rehashes of previous SOM, and though new to new members, I generally won't redo one that I've recorded before.
I like the idea of the SOM, but time is probably the biggest issue for most, and we just really don't have a lot of people on this forum compared to some.
Now you know just one of the reasons my SOTM would sometimes take me 2 months and a day to get to. And ditto for me on the time thing; ever since I moved out here to the "farm", my life has been cuh-RAZZY! But I still love SOTM; keep'em coming!
I especially like it when you choose songs I don't know; really gives me something to set my sights on.