The beginning is best made in small steps.
I’m not familiar enough with pure maps or @karry 's osm stuff. So I’m not sure what things should or should not be ‘tightly coupled’.
In any case, my suggestion about focusing on one provider was not about limiting the app, but providing a single default which would be the first goal of an organization to provide financing for. The idea is simply to get a org going to fund ONE key to support ‘ease of use’ for the base that, hopefully then donates for that fact, among others.
I’m personally going through a phase (ahem) where I’m giving up working for something that I helped create. So I’m in an ambiguous state about ‘founding’ things at the moment. On the other hand, I’m interested in the venture. But I don’t understand it clearly enough (I’m in public transport api and camera land at the moment). So, I tend to think of the KISS thing. Without getting into the nitty grittys of funding a tiling server.
Maybe we need a list of ‘units’ that need funding but could be founded/funded individually?