> Are you suggesting [...] they want to make money? Isn't the simpler explanation that maybe a 42-year old design is out of date?
I'm sorry I was too pithy. To answer your second question first:
Old aircraft are not inherently bad. The most famous case is the B-52, already in its sixties and when the current round of refurbishment completes (if it hasn't already) should continue fighting with airframes over a century old. The A-10 Thunderbolt (Warthog) is still in service despite many attempts to kill it as there is no replacement.
(Old aircraft aren't inherently good either; even the Harrier, despite being heavily used and not really having a replacement, eventually became too expensive to maintain)
The F-16 was brought up specifically in the article; the claim was that it is too difficult to upgrade its electronics, not that the airframe or engine were obsolete. Indeed the specific use case a new plane is being considered for is the kind of thing where an older, airworthy craft would be better (the station wagon vs Ferrari example from the article).
So for your first question, money: yes I am explicitly suggesting that. Without getting into the politics of consolidation in the US arms industry, since the B-1, weapons production has been structured in part as a jobs program (The B-1 was the first weapons system to explicitly have had its supply chain structured to have parts made in 100% of all congressional districts) while the purchasing procedures are so complex that they require ex military on the private sector side just to make them viable. That revolving door is not subject to any lobbying rules and is, TBH the only real retirement plan for senior officers below three star rank. And of course spending money on arms is always popular with the voters, as part of the "support the troops" slogan, even though the actual troopers, humans, get low pay, mixed-quality post-service health care (some amazingly excellent, other terrible) and are not protected against the depredations any number of predatory corporations while in the service. Oh, but that shiny gear shows off as well in the USA as it does in norks.
To be more charitable, generals and admirals also always want to push for the new and shiny because that's how they demonstrate status, in war and especially in peacetime. This is a social factor in all groups, this is merely how it manifests in military hierarchies world wide. Doesn't mean it's an effective use of funds nor that it necessarily improves warfighting (much less prevents it).