Clearly as later examples like Amazon have shown, auctions don't make sense for most product categories. I believe this is mainly due to psychological reasons.
Decision-fatigue is a real thing. People dislike having to think hard. In a fixed-price sale, the buyer just has to ask themselves one yes/no question: "Would I be happy buying this item for $X?" This is a very simple question to answer. In a sealed-bid auction, people have to ask themselves "What $X am I willing to pay for this item", which is a tremendously more complex question to answer. In fact, from a game theory perspective, you should never put in a bid that you're "happy with". You should put in a bid where you're exactly neutral between buying-vs-not-buying. Otherwise, you're leaving money on the table. This is asking people to make purchasing decisions whose outcomes will leave them explicitly not happy - a state of mind that every person hates putting themselves in.
Couple this together with the fact that the buyer doesn't even know whether they won the auction, until X hours/days later. And during this period of time, they are under a state of uncertainty, which is another mental state that people generally hate.
I think that for very expensive, non-time-critical and hobbyist items, an auction may work great. People may actually enjoy pouring effort into it because it is their hobby. But for any item that people just want to buy-and-move-on, auctions are a horrible mechanism. Perhaps one day when AI assistants make all our purchasing decisions for us, auctions will become the norm, but certainly not today.
