I think reality is that JM also doesn't put a lot of initiative into it. You can "loosen" the rules all you want, but if JM goes home after the gig to his family and doesn't show up with lyrics the next time, it's not gonna help you.
True. Loosening the rules
now may not help, as the damage has been done. I just figure that JM used to like writing lyrics. If it was something that was always valued and encouraged within the band, then he would find time to do it, just as he finds time to practice and learn the new songs and stuff even though he has a family. It would be one more "band-related" thing that gets prioritized in his life.
But he got shot down, and at this point, he hasn't written in a while and perhaps has lost the feel for it, just doesn't care to do it anymore, so even if the possibility opens up, it won't happen. But we don't know.