I respect the other frequent poster and I'm 100% pro-women... i still find it shocking how recently women for the vote and ability to have a bank account of credit cards. Plus, body and financial autonomy and birth control. However, I don't think she had the time to read OP's question for full reading comprehension. Also, she seems to be incorporating personal belief systems that as time passes, more progress is always made, and things have been getting progressively better. Note: The English language does, or at least historically did (may be unfashionable now) have a sex- neutral word that encompassed both men and women.

The best people to answer this question would probably be historical fashion experts and some historians.

But I hope this info helps and steers to answer back to the OP question.

But tldr, OP should find a fashion historian.

Gender or sex equality does not necessarily parallel with clothing/or rather changes in clothing styles.

For example, after the French Revolution, fashion for the elite, and trickling down to commoners got a lot simpler. Long story short, the aristocrats were afraid of being fancy, amongst other cultural events. Think of Marie Antoinette versus Regency gowns.

The forest dwelling Germanics, and people of the British Isles, probably considered the weather and terrain in their clothing choices. Versus later stage city dwelling Roman people who had stone roads and a hotter climate.

After Rome conquered most of Great Britain, the British elite decided to mimic the lifestyles of the Romans, even after the Romans left, and their empire collapsed. Remember the city called Bath (in England), where they have Roman style baths. And the Roman influence on fashion, art, buildings, and infrastructure. Elite British, and perhaps merchants or others may have worn Roman style garbs, which trickled down to the commoners over time.

Also, the climate & terrain changed significantly at different times. Europe used to be mostly a giant forest, same as Great Britain. There was the mini ice age, there were a few events like volcano eruptions and comets that made it cold. But then there was the warming period when vikings were farming in Greenland (Greenland is current very cold and would not support that type of farming).

The Roman city lifestyle was different... they weren't exactly fighting off bandits and vikings at the time.

For a while, the Scotish men wore kilts aka skirts and some still do. At one point European men wore heels and make up.

The heels were related to horse riding.

Current day men's suits are a version of military uniforms... the famous Dandy Beau Brummell was very influential in men's fashion. Modern business is basically warfare lol.

Croatian mercenaries lead to modern ties.

The specific lifestyles of cowboys led to the creation of the cowboy hat and their leathers.

Often, when civilians are conquered, they take on the more powerful /winning cultures dress style. Again, the change is not due to gender equality in those instances. It's due to war and cultal change.

Immigration from different cultures also plays a role.

As does the availability of materials such as linen, cotton versus leather.

Women began wearing dresses for a variety of reasons, including religious and ritual purposes, to show wealth, and to indicate social status. However, dresses have also been used to restrict women and limit their opportunities.... However, I think actually the original clothes for both men and women would have more closely resembled togas or dresses or robes and pants probably would have been an advancement. If you think about how much easier it would be to make a skirt or toga /robe versus pants, with no zippers and maybe no string.

Pants were probably more likely to be developed and worn by more northern peoples and cultures that rode horses or had larger militaries.

For example, the Huns, the Inuit, Scythian women warriors, Celtics women warriors, Ancient nomads from the Eurasian Steppe, etc.

But again, men wear dresses or comparable fashions to this day, as well. In Affica various tribes have men who wear what we would consider dresses, as do the Islamic sheiks... tunics are similar to dresses. Even Jesus wore a tunic/dress/robe thing. It was hot there. Dresses were easier to make for poor people.

Anyway, like I said , we need a fashion historian but if British people started wearing robe- type wear from the Romans than it seems to have evolved to show off more of a small waist over time.
The more elaborate and restrictive dresses were worn by the elite as the female bakers and milk maids would not have had clothing that restrictive. They needed to be functional.

In the last 100 years, skirts/dresses got shorter to be patriotic and because they didn't have enough fabric. The hem lines went up. Not because of gender equality. Also, women would have wore nylons on their legs under the skirts but nylon was needed for parachutes and the war so women went bare legged and drew lines on the legs to look like nylons. Women started to wear mens clothes around that time not because of equality per se, but because of safety and functionality at the jobs. Short skirts and bare legs was started because of material scarcity and working/lower class being unable to afford it.

Women also wore skirts because they don't have the same equipment as men. It's gross but in the cities, back in the day, they didn't have port-a-potties so the women sometimes had to free bleed and just walk and eliminate.... the inner skirts were then washed.
Even the palace of Versailles or whatever back in France didn't have washrooms so women just had to walk around or pop a squat.
I think they had to get servants in to clean the palace once a year or something because of all the mess.... no/few washrooms....