In the US, there are two overriding issues with the EHR - getting a bill out and getting a bill out.
There's a distinction here that is being missed between a Electronic Health Record (EHR) and a Practice Management System (PMS). The PMS usually handles scheduling, billing, claims, remittances, and maybe registration -- the business side of healthcare. The EHR holds the patient's actual clinical data. These systems can and should talk to each other: the EMR will need the ADT (Admit/Discharge/Transfer) feed from the PMS and the PMS will need the procedure codes to bill for from the EHR. However, the PMS is not a health record and shouldn't be used as one. You can't get a proper continuity of care record out of a financial tool and likewise will have a hard time doing billing with a clinical tool: they're specialized for different use cases.
Unless you are at family practice, the docs don't usually mess around in the practice management software: it's more of a tool for the front desk and accountants. On the PMS side we've had pretty good standardization of formats dues to HIPAA. The government had a pretty good lever here to force compliance: Medicare. When HIPAA went into effect, CMS set a deadline that sometime in 2004 (IIRC) they would no longer accept non-X12 claims. Since Medicare/caid are such a huge part of everyone's revenue stream, everyone had a real motivation to comply. This worked so well that when I left my previous job in 2012, our claims clearinghouse division was actually shrinking because the software to connect directly to insurers had become a commodity feature in most practice management systems.
There is, as far as I know, no equivalent government body that everyone interacts with for clinical data that could force a similar standardization across EHR vendors. I know where I worked we tried to support the IHE profiles as much as we could, but I don't know how wide-spread that behavior is.