I don't believe it is an easy way out. Most schools and businesses just don't want to waste time on being fussy of the amount of material on a woman's shoulders these days especially when the code itself isn't equal for men and woman. Who wants to set themselves up for a lawsuit. And there have been many in schools and workplaces that are unionized. There is one right now with a Pilots Union.
Me as a surveyor for most of my career I wore jeans. I took my career seriously and was well respected in the industry. Frankly being in a male dominated career a skirt would have been inappropriate. Lots of the tech industry has gone the way of Steve Jobs. Black turtleneck and jeans every day and I fail to see how that hurt Apple. The Silicon Valley which is boatloads of talent. Engineers usually in a tshirt, zipper hoodie and jeans and of course gym shoes. Zuckerberg has been know well for his tshirts, sweatshirts and jeans. Very successful. Their clothing didn't seem to call into question their ability lead or build awesome corporations and draw talented employees. In the fast-moving world of tech, the idea is to show that your'e not wasting precious time on something as vain as fashion, they aren't judgmental or catty about petty things like clothing but are some pretty talented people that have more things to focus on who is wearing what, the Code if anything is University casual. And it works. Likely why more and more firms are moving away from dress codes.
I am old enough to remember the poor RNs that were forced to wear white dresses and heeled white shoes with a stupid hat everyday in hospitals. That is a heck of another folly of a dress code gone bye bye. Getting patients in and out of beds, doing CPR etc in a white dress. My Nuns were in full cover from head to toe, couldn't see a hair on their head, no necks. Don't think it made them better school teachers to wear that in non air conditioned buildings. Don't believe little girls forced by code to wear a skirt or dress made them smarter. So what does that teach little girls that adults write dress codes requiring them to have exposed legs in school?
The one I like the most that has 'let it go' was SouthWest Airline. As you look at their attendants they dressed in the summer months, shorts and a polo where other airlines have for decades dressed their flight attendants in some unique costumes/uniforms and the ridiculous high heels on an aircraft. Me my favorite airline is SouthWest, usually nice and warm employees, fair price. Being more casually dressed in their industry doesn't seem to have affected the corporation or their success.