I think that's the point of the memo - not cancellation, but a drastically reduced F-35 buy.
For over the last 20 years it's been mooted that what the DoD needs is small scale R&D programmes leading to a couple of Sqns of next generation aircraft. No great engineering costs for entry to service and logistics, just to retain the engineering skills and infrastructure to ramp up if needed.
In the F-22 the USAF reached that point. In the F-35 maybe the USN and USMC are as well...