I don't think is accurate. While it might not be built in currently, the same is also true of something like SASS or even plain CSS.
The article describes a strategy for loading CSS in the most performant way given a variety of interconnected factors (mainly JS).
You could generate the Tailwind file, and then split it when the media queries start (they're all grouped in order of screen size) with a small bash script into separate files as a part of your build process.
You could have multiple build steps that analyze your component architecture and generate separate CSS bundles for each component. This is already done w/ most JS frameworks.
If your argument is one of the final CSS file size, that is not an issue. Tailwind only generates classes that you write in your markup. Most Tailwind bundles I have seen, are dramatically smaller than their CSS counterparts, and it makes sense when you think about how CSS is written.
Say you have a two UI elements; an article preview image and a user avatar. Say you want them to mostly display the same, but with some tweaks to the avatar to add a fancy filter on hover. Okay easy enough. Maybe you start with some sort of base mixin and then overwrite add behavior for the avatar. Over time, you add more and more tweaks to the avatar until one day, you get a call from the head of Design Department that the articles are getting their own special CSS filter. Okay, so now you extend the article. Over time the two continue to drift until you're overwriting anything that they originally shared in the beginning. The articles have different margins than the avatars and now marketing wants to allow users to upload images to comments. Does that extend the original mixin from 3 years ago? Maybe you think, "why do I even have this base class; can I get rid of it?" After some quick testing you remove the original mixin and go home for the day. Over the weekend, you get a call saying that the avatars showing user contributions from a fundraising event are all messed up. It turns out, the base mixin added `display: block` to the images, but when you tested, you really only looked at the logged in user profile photo in the navbar. Whoops.
Now take that scenario and multiply it by 100 devs on 20 different teams. We've all seen it. This is why CSS is often never deleted in large companies. Devs instead to continue writing ever increasing specific selectors or using techniques like BEM/OOCSS to stop the bleeding. It takes an insane amount of discipline to wrangle CSS on a sufficiently large project. Tailwind helps manage some of that complexity, and at least provides good guard rails for teams of developers by empowering them to know that a "small refactor" won't break an entire layout.
https://frontstuff.io/in-defense-of-utility-first-css
https://github.com/sarahdayan/utility-first-compression-demo