What do you think that is reason for that and will that change in the future?
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.
I guess that regulation is one of the keys to solve this. Legal obligations are getting more strict for everyone involved in financial industry and cryptocurrencies are especially sensitive. Still I hope the situation will improve soon because I would really like to see more crypto debit card providers. For me that is one of the services that is really convenient and enables me to spend Bitcoin in real world very easy and without issues.
In my opinion, crypto-sector is competing with the traditional financial sector. So, the growing interest in cryptocurrencies weakens the interest in the traditional financial sector. Thus, the institutions are trying everything to prevent this rise. On the other hand, cryptocurrencies are still popular for money laundering and the laws are in this regard still lax. It would be an outrage if a company is being associated with money laundering. Of course, there are companies like Western Union where money laundering may occur but they have some guidelines to follow to prevent such cases. A solution to that is setting clear laws for the debit cards or having more vendors who accept cryptocurrencies.