1. The Babli covers more interesting stuff, and covers it more thoroughly. This is largely a function of the fact that the Yerusalami’s development was interrupted whereas the Babli’s continued longer (goyim can be a nuisance at times, can’t they).
2. Since the Babli is more respected and more widely studied, it was printed more often. There isn’t even a universal structure to a Yerusalami page, whereas the Babli has had a set “Tsuras ha-Daf” for 500 years.