Wow, what outdated thoughts? Saying that US carriers are "poor" and only giving SQ as an example? The big 3 US carriers Biz products are for the most part superior to the Big 3 European carriers in every shape way and form SQ? Yes of their 5 current Biz products 3 are superior to US carriers, what good does that do you to fly between Europe and the United States, other than one singular route to FRA? Also, just to be clear that every carrier in the World is happy to sell you an upgrade before flying, what you are after is a knock down last minute upgrade deal, which is something that US carriers do not engage in, for that matter even with miles, many have restrictions of 24 hours or whatever. SF there are PLENTY of markets where SQ is the most consolidated carrier available and undercuts just about everyone else, it is bassed on competition, and nothing else.
Honestly when I am flying on a $6k ticket, and the last empty seat is next to me, I would prefer if some guy on a $600 RT does not sit next to me for another $500 upgrade. Also as noted above, keeping up standards, inasmuch as no regular Biz pax will spend big money every time if they always know that they can upgrade and do it for significantly less than the RT Biz price.
Some carriers have experimented with auctions, however they never work the way that they are intended.