How is "widescreen" objectively better?

Considering that “widescreen” was in part intitiated to compete with television, I think it was serendipitous that the wider aspect ratio is actually more aesthetically pleasing.
IMHO of course.

After shooting 35 and a lot of HD nowadays, I find the compositional possibilities over 4:3 are more engaging. I feel like the wider ratio implies movement or aniticipation of movement. Or it can really magnify isolation. I see more opportunity for choreographed movement across the widescreen. You just can’t beat panoramas that are, well, truly panoramic.
It’s a blast to play with light, shadow and focus across the wider canvas.

Are we living in different universes?

For the record, I don’t believe anybody ever said such a thing. There never was such an article. You are remembering wrong. Even on the internet where you can find people who will say absolutely anything, no one could possibly say this.

If you go to the Widescreen Museum that I already cited you’ll see that widescreen was around for decades before television and everybody knew for that entire time that it had superior aesthetic possibilities. It’s not serendipitous. It was a known fact that they exploited.

It’s quite easy to test the aspect ratio of your vision. I just took a ruler and held it two finger width from my nose, and I could see about 7-8 inches of length vertically, and the entire length of the ruler plus some horizontally. If I had a yardstick, I could measure it exactly, but my field of vision is at least twice as wide as it is tall.

I’ll add that while yes, 4:3 ratio is wider than taller, it’s still inferior to an even wider aspect ratio; simply because it’s still too shy of how we naturally see the world around us. The basic idea, if you’re going for immersion, is to fill your peripheral vision as much as possible. It’s painfully obvious our peripheral vision is far more sensitive, and noticeably wider horizontally as opposed to vertically, so it makes the utmost sense to try and maximize that. Our brains are simply wired to take in a scene from a side-to-side POV, so when we view mediums that try to mimic or immerse you in a false reality, wider is better. Period.

Of course, it creates more leeway compositionally, gives the director room to breathe, and generally feels more grander when it comes to myriad settings, because there’s more room for landscape and distance to block your objects/characters across what we can dub the ground plane.

One more thing, the idea for IMAX is to try and completely envelop your FOV in the film, bleeding into the boarders of your ever weaker peripheral vision. There is no demarkation to our sight, but a fall off of detail and focus, and IMAX attempts to fill as much of that as possible to wrap your vision in the medium. Traditional theaters obviously cannot do this, so they settle for the next best thing: A naturally wide aspect ratio.

Now, when you want to watch a movie at home, it only makes sense to have a set that can best accommodate and reproduce the format of the original film.