Medical information system vendors only care about making a profit, not implementing actual solutions. The discrepancies between systems can lead to bad information which can cost people their life.
VistA was useful in it's time but it's hardly world class anymore. There were fundamental problems with the platform stack and data model which made it effectively impossible to keep moving forward.
It wouldn't be appropriate for the federal government to push any particular product. They have certified open source EHRs. It's not at all clear that increased adoption of those would improve patient outcomes.
If I understand correctly, Estonia made their own EMR/EHR from scratch. The government produced (and commissioned?) software is all open source. https://koodivaramu.eesti.ee/explore
EMR software seems like something that shouldn't be that hard. It's fundamentally a CRUD. Sure, there's a lot of legacy to interface with, but medical software seems like a deeply dysfunctional and probably corrupt industry.
I'm sure there's a lot of work, but hundreds of millions per deployment is not justifiable. The Finnish EPIC deployment has cost almost a billion euros.
Estonia's from-scratch system was reportedly about 10 million euros.
That's basically medical information system vendors.
The fact that the US hasn't pushed open source EMRs through CMS is insane. It's literally the perfect problem for an open solution.