A lot the decision-making we do is around trying to improve the health outcomes for large populations of members at scale. When dealing with millions of members, interventions that require lots of effort and time are hard to scale up. If the data shows members with annual checkups have better health outcomes on average than members without annual checkups, that is something that's relatively cheap and easy to do with potentially significant impact.
There are other benefits to annual checkups as well - catching an expensive condition early can be the difference between a $100,000 episode of care vs. a $10,000 episode of care.
To be honest internally I've noticed the tide is shifting on annual checkups. Physician time is limited and every slot is valuable. I believe we're currently exploring virtual care options as a better alternative.