I think part of their problems with joint songwriting occurred when that changed; Glenn has said that after the huge success of Hotel California, they both were afraid to voice ideas in case they weren't good enough. It made the process a lot harder.
On another note, Glenn gets outraged over a critical review c. 1975:"Some guy reviewed us for the New York Times and labeled our songs escapist rock. Now to me our songs are more realist rock, confrontist rock, than anybody's. [...] What we're doing is all stuff that happened to us. We don't make any of it up. It happens to us in real life - a relationship with a girl, a spiritual thing, whatever. I hate those stupid labels. I hate when people call us a country-rock band because they are so full of it. We can do anything! We can do rock and roll, we can do country music - anything!"
You tell 'em, Glenn!