Corsair1963 wrote:Fact is the USAF has a plan to retire the F-15C soon.....(Yet, feel free to believe what you like?)

It doesn't sound like it is going to happen anytime soon. Otherwise why would the USAF contemplate spending scarce funds on this aircraft?
"In general, the fighter force structure must include a mix of legacy aircraft to maintain required capacity. The Air Force will
continue to invest in sustainment and modernization of the F-22 (enhancing lethality, survivability and connectivity), the F-15C/E (enhancing radar, avionics processing, and select defensive systems), the F-16 (improving the radar, avionics processing capability, and defensive systems), and the A-10 fleet (maintaining sustainable combat-coded A-l 0 aircraft and
ensuring the overall health and continued viability of the platform) until a time when recapitalization of select legacy aircraft
is directed."
From the Annual Aviation Inventory and Funding Plan Fiscal Years (FY) 2019-2048 - published in March 2018.
https://apps.dtic.mil/dtic/tr/fulltext/u2/1062648.pdf