Well, do you happen to know how many other people are repeat buyers of similar products? Maybe a large number of buyers end up buying a second set of speaker stands because they don't like the ones they just bought or because they're enthusiasts who gift them or have multiple audio setups. Just because it seems unlikely someone would be a repeat buyer in a given product category doesn't mean it isn't profitable to target every buyer as if they might be.

Almost no one? Obvious anecdote alert, but I don't know a single person who shops on Amazon who hasn't made the exact same observation. Many/most big ticket items are, for most people, a once-every-X-years purchase, and yet Amazon's recommendation system can be counted upon to suggest another TV, another DSLR...it's remarkably terrible for a system that's been under active development for twenty years.

Plus my speaker stands haven't even been delivered yet. Amazon knows this.

Annecdata ahoy: I bought a TV from Amazon and they stopped showing me more TV's after I rated it. Maybe they think you're still in the market and might send those stands/DSLRs back because you didn't rate them.

If Amazon's default assumption is "The product we sold you was garbage, maybe you want buy a different one instead" then I think they have even bigger problems.

EDIT: And if I liked it so much that I wanted to gift it to someone, why show me the 5 competing stands instead of the one I know is good from personal experience?

A person who has multiple audio setups wouldn't need prompting to about it either. If they like the ones they got, they'll order it again. If they didn't like it, they'll look for something else without needing an email about it.

It's an interesting point, but I would hope that they would factor in the negative impact on non-repeat-buyers. Some buyers(at the very least: me) feel remorse or regret over their purchase if they are presented with a bunch of other options which may be better or cheaper than whatever they chose to buy.