I'm pretty sure in the US the barriers are also commercial, ie, Epic (a huge hospital software company) is not going to make it easy to do digital transfers of their patient data to non-Epic computer systems. Only the small-fry software companies will want this.
What needs to happens is for the US federal government to issue a mandate: if a hospital wants to get federal dollars (Medicare, etc), its computer system has to comply with the FXHR rules (Federal eXchange for Health Records, or whatever they want to call it). To establish FXHR, they get the top 5 vendors in a room and tell them that they WILL come up with a data exchange protocol and format within x months. They did this with HIPPA, they can do it with data exchange too.
And it is sorely needed. I went to Mayo Clinic for a week, which generated 80 pages of medical reports. To get these transferred to my regular doctors, I had to call Mayo, request the transfer, and they had to schedule the transfer, which sometimes took up to a week. This isn't because they are inefficient (far from it). It's because when they do a fax, sometimes the fax machine isn't on, so it can't go through. They have to retry until they get through. The receiving machine ran out of paper. Etc. It's ridiculous.
Beyond that, I watched my eye doctor try to flip through 80 pages of crap that mostly didn't relate to him to find the pages that were eye related. None of this has any structure; it's just a bunch of pages of text. Horribly inefficient use of his time, and very likely he would miss something important. You want to see blood test results? Well, I had about 10 of them testing various things, and the lab results are spread all through the report. Good luck finding what you want. Truly a mess, and the large software companies have zero incentive to fix this problem. Their goal is to be "the one to rule them all", or at least one of the few. And when there are only a few, there still won't be any data exchange, because they will be duking it out with each other.
Government screws stuff up all the time, but so do private companies, and government is the only player in a position to force the private companies to do the right thing.