What you said is correct, but only for a rational person. Note the wording of your parent comment: "it looks like".

Many if not most people will buy the thing for $X, then complain that someone else scored the same item for $X - $100.

It's like the complete opposite of "bidding fee"/"penny" auctions, which are very scammy and provide plenty of profit to the auctioneer, but people feel like they could get a great price. But if you make the math (and notice the dark patterns and know that usually there are also fake bidders...) you can see how much of a scam they are.

If it starts at $10000, then the number of people that buy right away and get upset when it drops by $100 is roughly zero people.

Once the price has already dropped more than ten times, and the site says when the next price drop is, people will figure it out well enough.

"Dumb people are going to be unhappy" is a strange argument to make.