And yet, late last year or early this year I was able to buy a replacement charger [edit to add: they sell the battery too] from Dell for my 2013-model-year Latitude laptop. Not the exact same model as was originally bundled, but it's still new from Dell, still officially documented as compatible with my laptop, and still works fine with it in practice.

You described Apple as a consumer goods company and called this scenario satire if you just substitute a different company. Keep in mind the sale to OP was made by the much less consumerized Apple of 2014, not the "you can't touch /System without disabling important protections" Apple of 2021, and was from a Pro laptop line ostensibly targeted at business use cases, not a consumer model.

The expectations of OP for a top-tier business laptop seem quite reasonable to me, both in the past and in the present. My laptop still meets my needs well enough after more than 6 years of use (yeah I bought it in 2014) that I haven't been able to justify the purchase of a replacement, even though I could afford one if needed. Dell's offering of guaranteed compatible new parts reinforced both that decision and my openness to Dell business laptops whenever I do upgrade, since it's not a planned obsolescence trap.