Remember, the Cerner acquisition enabled an essentially permanent beachhead for Oracle in the VA. It will pay off over time in 'we already run Oracle' across many dimensions of government.
They had a very kludgy, homegrown, but generally well-liked and cost effective EMR calls Vista.
The fact that it was cost effective, but required internal expertise was exactly what led the Trump administration to kill it.
Now they are transitioning to Cerner, the worse of the two major commerical EMRs by a fair margin, for many billions of dollars to the Kansas-based company, now owned by Oracle.
You can fill in the details of why this is happening by looking at where the CMS appointees at the time have landed in their post-government careers.
See the career of Seema Verma from last DT admin.