Just resize your browser window: it's not the site's job to guess how you want content displayed.
I loved browsing the web in the 90s: I had a half-width browser window on one side of my screen, an editor window in the upper quadrant of the other side and a console window the the lower quadrant. It was great! Then suddenly every website decided that I must have a full-width browser window, and was ludicrously narrow with a half-width browser. And they all stopped using and started abusing CSS. And then they all started using & abusing (but I repeat myself) JavaScript.
All I really want from the Web in 2018 is the experience I had in the 90s, and I can't get it any longer.
Also this format works great with the browser's "Reader" function.
At a certain point you have to recognize that even little CSS (max-width, font-size) can actually be a good thing, and when a site lacks this it doesn't make it somehow inherently better, it just makes it harder to read and I am nearly as inclined to simply hit the back button as I am on Medium articles. It's two ends to a horseshoe. The best place to be is somewhere closer to the middle.
Here's the thing: I don't want the font or the images to be bigger, I want columns to not be this absurdly long. The only way for the user to achieve it is to resize the browser window.
There is a "max-width" CSS property for that. No framework or JS required, just a modicum of care.
> Also this format works great with the browser's "Reader" function.
It still would using max-width.
That said I am not defending current state of Medium.
[1]: https://i.imgur.com/VXestU1.png