We did try it. We tried it for a couple of millenia. It was much harder to understand and our collective mathematical output as a human species was much slower than it is now.

Shorthand is better.

No, I don't believe you. Mathematicians love inaccessibility.

It's not that.

You know when you go to a foreign country, ask for a particular thing in a restaurant proudly in their language that you picked up on Duolingo the week before and the waiter starts talking to you quickly in their language and you lose it completely.

We are just that waiter. You didn't learn the language or get the prerequisite skills. So do that or don't bother. It's not easy and there are no shortcuts.

Consider the formula (a+b)² = a² + 2ab + b². How would you name the variables to make it more “readable”?

The square of the sum of two quantities equals the sum of the square of each quantity plus twice their product.

So much more readable! /s

Even if i agreed with you that full words/phrases were easier to parse, any gains made here are easily offset by how much harder and laborious it is to manipulate them on paper