I wrote up a project plan that details the players and some of the steps to get HL7 data through the traditional integration methods that exist today. Check it out: https://catalyze.io/learn/how-to-integrate-with-epic-or-any-...

I think FHIR only helps this process if it standardizes/centralizes security. So much of the process of setting up integration is getting whitelisted by an organization and setting up VPNs and other security measures that have nothing to do with HL7 or FHIR or IHE profiles. If startups have to establish credibility and integrity at each hospital they go to, the cycle will continue even with a public API.