I'm guessing it's due to Bitcoin's legality and regulation. Every country has its own regulation and most of them aren't even crypto friendly. Will that change in the future? Once governments have solid rules about crypto I'm sure a lot of vendors will start issuing crypto debit card again. But that step isn't going to happen soon, I predict. It'll take more years. Bitcoin is already 10 years old and most govts still don't have a set of fixed regulation for cryptocurrency.