I think this goes beyond supporting countries. Generally speaking Stripe is a pretty limiting gateway as is Paypal. Custom gateway support or perhaps a more open minded gateway like Bluedog would help with industries that are not supported by whats currently available.
I’m specifically talking about guns here… its a legal product in the US but Stripe, Paypal, Google & Apple do not support it. I’ve got a few potential clients that would jump on board in a heart beat but without a proper gateway or at least the ability for me to create a custom one, I cannot help these folks.