ISEA seems very relevant as an organization. Their history is very similar to ours. Regarding the financial model – I’m surprised that they manage to make that work. Perhaps institutions actually see a value in associating with a network in this way. Not sure if we could emulate that, though. Our audience may be too small.
Here is another example, which is the network TekLab, run by a collaborator in Norway. It is funded by money from regional uni development + a grant from the Norwegian Research Council. https://teklab.uib.no/