That article is written by someone who doesn't understand what's going on and can't communicate what's going on. About par for the course about stamps in the general press. Commemorative stamps are not valid for postage? Do tell.
In a blocked link repeating a Dec. 7 1998 Linn's article from the same time:
This one makes more sense, the "upselling" of proofs and trial colors. Wonder what became of this? Because...https://www.nytimes.com/2020/02/21/...e-books.html
This is perhaps where the money went and for even further "upselling". So then nothing happened in the Monaco incident.
Which reminds me, whatever became of stamp investment guy Marc (Armand) Rousso and his wall of bank boxes probably full of Sand Dunes sheets? And his US stamps certified by... Scott(!)? It's not the art investment guy, who is too young.