Another approach might be a hybrid, with a closed-source binary "core", and open-source code and linkage glue between that and OS/other libraries. And an open-source project with one-or-few officially-supported distributions, but welcoming forks or community support of others.

A large surface area app (like Google Earth?) could be less than ideal for this. But I've seen a closed-source library, already developed internally on linux, with a small api, and potential for community, where more open availability quagmired on this seemingly false choice of "which distributions would we support?"