Concur, it is a key player in the decision tree matrix when unit conversions are discussed at the National Guard Bureau level.
If using capabilities on an very specific Orange vs Orange contrasting argument there is much validity to your statement. Back in 1997-2000 during my first staff weenie tour as a Maintenance Officer there were 13 variants of the C-130 within the inventory it was a nightmare of sustainability.
Having been the Tactical Airlift Branch Chief at the Air National Guard Readiness Center - ANGRC (2013-15) there were/are a myriad of reasons to keep the legacy models moving forward. First and foremost the full scale wartime effort requirements to meet a 1.5 or 2 front posture (always fluid/changing environment based upon current and future threats) calling upon the Reserve Component = RC (the term used for Guard/Reserve combination) is mandatory with nearly 500 tails on the books depending on your count that day. It has decreased due to several unit conversions to UAV, C-17 and other platforms/mission set requirements. Other headliner reasons include the aforementioned political aspect no doubt and the always looming issue of strategic budget impact. You cannot meet the Quadrennial Defense Review dictated by the National Defense Authorization Act (NDAA) by simply converting all or most units with limited funding or simply closing them down (And then the politics become truly ferocious). Everything gets divided by each service at the 50,000 foot level as it finally makes its way down to each and every MWS and the capability it provides at the 500 foot level. As one simple example, the Army has airlift requirements to meet its wartime objectives when they push full scale or tilt and that calls for much more than the Active Duty can provide, hence the Reserve Components existence is mandatory. All services have an “Authorized Strength” Limit and are bumped up accordingly as the SECDEF approves dependent upon the contingency requirements. We also have active duty folks (Subject Matter Experts - SME’s) working with us on staff within the NGB/ANGRC HQs to assist unit integration/conversion/mission statements, etc. and my fellow Strategic Airlift Branch Chief was active duty and retired (lucky old bastard left me with it all - great friend even as a Nav,) so I had to take over both branches. Not only 20 C-130 units, 20 Tanker Units, 5 C-17 Units, and OSA. O-6 got pushed to Deputy A3 and they threw me in his spot overseeing all Airlift and AE Ops with a Total Operating Authority (TOA) of over $11B not million. That drove me up to the 30,000 foot mark for almost a year before an actual O-6 showed up when I left for Homeland defense. Job was mine, but I chose not to struggle thru PME during my staff horror. Not that I really had the time being on call 24/7. Staying O-5 helped me land the Homeland Defense spot on the beach I had been eyeballing 2 years prior. Apologies as I digressed.
*Zero reason to keep the C-141 around due to the superior performance of the C-17 and that was broadcasted by Big Blue back in the day. Once again, a very true observation 1 on 1. What the active duty failed to realize was despite its increased capabilities/cargo load, etc. they could not be in as many places at once with far less aircraft, hence the ever increasing aircraft procurements over a prolonged period. Other politics were involved, but bottom line is the footprint of nearly 300 C-141s cannot be filled by substantially less aircraft no matter how capable. Initial order was 120, then up to 160, 180 and finally 223 C-17s. Still more then 60 shy of C-141s but far better than what they thought they could do with far less. Very costly, but necessary to maintain a substantial foot print and how many times have you seen USAF aircraft procurement increase that rapidly from initial request other than UAVs, but that is new technology to be honest. Big blue even approved “Core 63”, an upgraded 75% all glass version designated as the C-141C model as they needed to extend the viability of an older aircraft (63 of them in the Guard/Reserve) while waiting for fresh off the assembly line C-17s to fill the huge gaping hole of airlift. This was my baby as the Program Manager during my first staff tour as a MX Officer and I eventually flew it as well after pilot training. Pacer Crag (KC-135 Cockpit/Avionics Upgrade) was the other debacle but don’t blame yours truly as I was 2nd in charge laughing at my boss pulling his hair out more than me. Trust me, I wish we could swap out aircraft at a rapid rate giving our warfighters far better capabilities they deserve without a limited annual budget, procurement rate and bureaucracy involved.