Chivalry is a separate thing from having manners. A gentleman is someone who has manners.
Chivalry died when history moved off from the Middle Ages. Being a Gentleman became a detriment after the 60s. It wasn't the rise of feminism that killed off a man being a gentleman. It was the 80s and greed and excess that killed off being a gentleman.
Manners are dead.
My Dad said that a gentleman can be recognised by
He never drinks from a bottle
He remembers to remove his hat when going indoors
He never leaves the toilet seat up.
Manners was always about knowing the right way to do things, about treating people with respect.Also of course it was a demonstration of self control.