And that’s why people don’t write equations like that

Says someone who clearly hasn’t looked in any Maths textbooks

If you wrote 6 + 4 / 2 in a paper you’d get reviewers complaining that it’s ambiguous

Only if their Maths was very poor. #MathsIsNeverAmbiguous

Working mathematicians never came up with PEMDAS

Yes they did.

which disambiguates it without parenthesis

It was never ambiguous to begin with.

Noone else does it that way

Says someone who has never looked in a non-U.S. Maths textbooks - BIDMAS, BODMAS, BEDMAS, all textbooks have one variation or another.