Why does vicious competition exist in the mobile payment space? All these solutions only introduce a convenient middleman between the credit card and the physic

Why does vicious competition exist in the mobile payment space? All these solutions only introduce a convenient middleman between the credit card and the physical store. Is there some sort of profit motive involved here, like fees off every transaction? If not, I have no idea why mobile carriers and retail stores are jumping in to try to monopolize everything if it's just a convenience.