They already tried that in the 80s

https://i.imgur.com/URSlmP6.jpg

They did for a while in the 70s and 80s. They were usually disguised as football team gear or running tops, but guys had half-shirts for several years.

Unfortunately, the 90s and 00s were relatively more conservative, and they disappeared. Maybe it’s time to bring them back.

Middle aged overweight women scarcely wear crop tops either.

we're fat

Definitely not a “never” .

In fact I hail from a European culture where the traditional grab has men proudly showing ( a lot of) midriff. (Detva region in Slovakia)

https://imgur.com/a/oSPdcxI

As others mentioned western/American fashion had sporty types wear crop tops in the 70s-90s

Here is Will Smith wearing a crop top in Fresh Prince From Bel Aire https://imgur.com/a/0OAZRpi

And yes - if you hang in certain circles men wearing crop tops is still perfectly acceptable. But currently it’s usually associated with femme-presenting queer men of other wise gender noncomforming people.

Straight men seem to have have shunned the look (as they tend to) when it became associated with queerness.

And. Of course all of this is US centric. Plenty other cultures and fashions out there.

Ps: Yahoo seems to think it’s time to bring the crop top back. So hey - you can be a pioneer: https://www.yahoo.com/lifestyle/return-men-crop-tops-why-210039991.html

Too fat, belly cold.

1. It's clothing that looks beautiful for the young and the fit

2. It now may be associated with other sexual identities

Some other already gave good possible explanations to this, but I am adding my own subjective uninformed view on this:

Not many people may actually like wearing crop tops but they do it for 'fashion' reasons and those fashion reasons so far dictated that women are the ones who have to wear them.

Me, as a man, haven't personally tried crop tops, but it feels to me like it would be uncomfortable. It feels actually uncomfortable to me when sometimes I wear an old t-shirt at home which has become shorter leaving some small lower parts of my back or abdomen uncovered. And it's not because of any social construct, I live alone and nobody can really care about what I wear, so it's not that. But it's like feeling cold on the lower back of my torso but warm in the upper part. It just feels uncomfortable.
That's just my personal feeling but I can imagine more people could feel the same.
So I can imagine wearing a crop top can give a similar uncomfortable feeling?

But sexualization of women required them to expose more parts of their body (most of their torso) while covering those ones not considered to be decent enough to be shown in public (breasts). But that sexualization and exposure of their bodies is something that is usually not so much required from men.

I think the original question asks why not so many mean wear crop tops as a choice they make, but I think it hasn't been so much a choice for women as it may have been a command from sexualizing fashion and the heteropatriarchy has determined that the uncomfortably and exposure of their bodies related to crop tops is something women have to wear not always because it's their choice but to comply with sexualized fashion standards.

I am not a woman or wear crop tops either, so I may be wrong on all this, I'm mostly just thinking out loud 😄

best I can do

I roll up my top when I'm at home but imagine walking around like that. I'm not sure what they are called but I imagine it would be more easy to wear the baggy crop tops that look like mini ponchos/ shoulder dresses

That body hair is private

Because being tight is considered a beauty standard for women, not so much for men. For men this is mostly upper body muscle (shoulder, arms). A vest top would he an equivalent, and you don't see skinny guys wearing that either.

Almost no men have the body for it but it does look good on the ones that do. Just like thongs

I don't think I would want to even if they were popular.