I doubt that's going to drive a lot of OSS support, if the backend is still proprietary.
I think the GitLab or Nylas model works better for open source companies: open source the whole thing (or most of it), but charge for a hosted solution if you don't want to figure out how to git clone make install.
The GitLab model is actually: open source the whole thing and offer some more exotic features in a commercial enterprise version. The hosting on GitLab.com is free and GitLab only acquired GitHost when GitHost was announcing going out of business.
Maybe you're thinking of Wordpress (Wordpress.com offers paid hosting)?
> I doubt that's going to drive a lot of OSS support, if the backend is still proprietary.
There is plenty of support for Google/Dropbox/AWS etc, all proprietary-backend-driven APIs. If the API is good OSS developers don't mind too much, and they can always clone it anyway.
I think the GitLab or Nylas model works better for open source companies: open source the whole thing (or most of it), but charge for a hosted solution if you don't want to figure out how to git clone make install.