This is a great use of data to make a compelling case that sizing sucks for women's clothing! I do wish it attempted to answer the question at the end, though: "Sizes are all made up anyway — why can’t we make them better?" Like, why doesn't the market solve for this? If the median woman can't buy clothing that fits in many brands, surely that's a huge marketing opportunity for any of the thousands of other clothing…
I'm pretty sure everyone who cares about getting a good fit (and isn't simply trying the clothes on in person) is looking at measurements, which you can usually find for any half-decent vendor (though it may take some poking around their site). The best have it per-garment (or per-cut), less-good but usually still alright is having a guide to the measurements they base their sizing off of. Even guys can't really get…
On the other hand, I have never found trousers in a standard size that I would find comfortable. I have always worn only either completely bespoke trousers or standard trousers that have been customized for me by a tailor.
Unfortunately, where I live tailors have disappeared. For now this has not been a problem, because I still have many bespoke trousers made a long time ago. I wonder what I will do when I will need new trousers.
This is not an absolute size related problem. Many years ago, I have been obese for some years. Then I have learned to control my weight (after many failures), and for the last 2 decades I have been a relatively slim male of average height.
Despite this, I was content with standard sizes neither when I was obese, nor now when I am slim.
I am wondering why a lot of professions that existed when I was a child have become non-profitable, because the existence of cheaper alternatives today still does not seem a sufficient explanation. I have grown in Eastern Europe and absolutely everybody (except those belonging to the hierarchy of the ruling party) would have been considered extremely poor by today's standards. Despite this, most people could afford bespoke clothes of very high quality compared to what is available today and the tailors who made them had decent revenues.