For example aren't the documents and browser apps open-source? How many have contributed to those? 1(well maybe more?) guy for the documents and a few for the browser? Well I don't know how hard it is to contribute to those so that might be one reason if it is difficult.
As the community has pretty much exhausted their possibilities and done things in the open source parts of Sailfish, it's now up to Jolla to eventually hold their part of the bargain.