I have no idea what people are talking about with recyclable K-cups not made by Keurig being more expensive than Keurig-branded K-cups. I've never seen any that are MORE expensive - every one I've seen has been LESS expensive than Keurig cups.
Keurig now offers recyclable K-cups on their own brand that is the same price as their other K-cups.
For anyone to whom recycling K-cups is important, there are low cost/same cost options. If one is not into recycling everything, whether K-cups are recyclable or not is immaterial - they would most likely not recycle though they are able to.
You can't force or guilt people into recycling beyond local ordinances, not eating meat, spaying or neutering pets, not wearing fur, and a whole lot of other things. Admonishing people not to buy something that can't be recycled is pointless.
Life without Mexican food is no life at all