Note I am not saying that using http RESTful FHIR is a bad idea, for green-fields it is a good choice, likely the best choice. Just that nationwide, there are considerations that are beyond http REST concept, that are indeed special in healthcare.
Note, I am not saying that "let many flowers bloom" is always inappropriate. I do think that it is most of the time inappropriate.
imagine a fancy graphic here that shows three sources each of the types: e-mail, SOAP, and REST talking to three consumers each of the types: e-mail, SOAP, and REST