Printing “this shit is milk” on a bottle is dirt cheap. It’s practically free. They probably already do it with the expiration date.
Problem is, some bright-eyed fuckfuck at PepsiCo realized they could sell more shit using labels with no visible dot matrix and a color palette with vomit-inducing vibrancy and 69 million shades. Approximately 90 seconds later, everyone else decided that they need to wrap their plastic in some plastic to “stay competitive”. The industry collectively stuffed some lunch money in Ronald H. W. Gore’s titty pocket, and here we are, decades later, with a mountain of unrecyclable garbage that no one even knew couldn’t be recycled. And it’s not even their fault, for the same exact reason we don’t expect people to know not to lick the lead paint off their mid-20th century coffee mugs.