Honestly because those formats are more restrictive (in an engineering sense), proprietary (in the sense of who really controls them) and difficult to parse. Y

Honestly because those formats are more restrictive (in an engineering sense), proprietary (in the sense of who really controls them) and difficult to parse. You’d need some sort of special subset of the format to make it so that people’s use didn’t obscure information, as is easily doable with scrambled PDFs and the like. You’d have to validate that format and reject submissions that didn’t use it. Laziness would probably lead to whatever the printer driver produces being the de facto standard.