I'd definitely like to see CapOne come to Samsung Pay (on paper, Samsung Pay is great, but its lackluster bank support kind of sucks), but I'd like to note that they implemented tap to pay on their own mobile app, and it's possible the reason we've yet to see CapOne on Samsung Pay is because they're trying to get people to use their own app...and while more choices are great for the consumer, sometimes businesses don't make decisions with the consumer's best interests in mind.
I knew they made their own application and I like their effort but the only thing with their app is that its only useful at stores with NFC support which is lackluster in the United States. If they got on board with Samsung Pay, there could be a possibility of more people using it if they have Capital One
I should stress that this is purely a hypothetical (possible reason why CapOne is one of the big boys still not found on Samsung Pay).