The problem is that the protocol used by imaging devices (DICOM) is ancient, and connecting with a DICOM server is a pain. There is a sort of modern standard that I've heard talked about called DICOMweb, that I think will be hooked up with FHIR and be made apart of the USCDI eventually (probably). But we still aren't very close to being able to see X-rays on our phones.
Also, one funny anecdote I've heard from working in this space is that some doctors do not like the Clinical Notes story (https://build.fhir.org/ig/HL7/US-Core/clinical-notes.html) since it means that their personal notes about their patients will be made available directly to the patient, something that was not possible in the past. Doctors often write down their real thoughts about the patient in there and can say some things the patient might not be happy with.