It depends on what we mean by support. In Dublin you have Rovers with their fans and money, and 2-3,000 between Pats and Bohs (and Shels). Cork for sure, Derry yes, Dundalk yes (though we know what'll happen in a downturn). Sligo are sugar daddy too but with 1,500-2,000 fans. Unless it is just ripped apart and starts again, which would mean Drogheda goes, Cobh, one of Athlone or Longford. 10 pro "franchises" with 2 groups of 20 (north-south divisions) below it with 1 or 2 spots available depending on play-offs.
Or else there is a proper pyramid and have at it.
In Russia all clubs are sugar daddied (can I say that?). In fact in Eastern Europe I could not name a single one in Russia, Ukraine, Belarus (even BATE), the Baltics, Moldova or Serbia who are professional and not dependent on a single person, company or government for survival. BATE have ploughed their money into facilities and coaching, but they still pay very big wages. So if they can thrive, so can we.
10 fully pro clubs, backed by business, fans and government (as they did/do in Norway) and we might have a chance.