Because there’s very little overlap between people who need them and people who know that it’s an option.
The people claiming them would primarily be people like me who do know how it works, know that I probably won’t use it, but am going to take it anyways, because it’s free and because it is within the realm of possibility that I need another cable as a temporary replacement until I get another one.
Simple solution: if a device you sell comes without charging cable, it has to be written in large letters on the box that you have the right to claim one for free (like cigarette health warning) and the seller has to inform the customer before checkout
Then everyone will claim one and you’ll increase waste.
The whole reason they’re removing the cable is because of pressure from governments not to waste materials including it.