Jon, you explained my concerns exactly. We are not involved in MU, and have perhaps a 3-4 year practice horizon. An exit strategy is vital, and using version 6.5 forever would suit us just fine.
After Pri-Med bought AC last year, we started getting calls from concerned Doctors with the same perspective.
Our standard service delivery is to onboard an existing AC client quickly on a platform that can run without interrupts or tinkering for years to come.
For those that continue to operate in their office, that is why we recommend a RHEL/CentOS server that can host the AC 'server' far into the future long after Win14 debuts without having to upgrade Windows or AC. If the server also has terminal services onboard (or as a separate VM), the rest of the office can have moved onto Chromebooks, Macs, Linux, wearable computers, flex-screens - whatever. AC lives on it's own private enclave.
We talked extensively about this during the Meetup Weekend, so hit me up if you want more details.