Another underlying issue with interoperability is that healthcare IT companies can integrate and share information like this article suggests.

FORBES: Is It Happening? Electronic Health Record Vendors Take Steps Toward Interoperability

An average practice could have the need to interface 5 different systems to the EMR within its practice then add on the interface to exchange information outside the practice and you get a better picture why healthcare providers are not investing in interoperability.

FORBES: Is It Happening? Electronic Health Record Vendors Take Steps Toward Interoperability