Ask HN: Why don't we hear about startups going against Visa and Mastercard?

With network connectivity almost every where and cheap now and the proliferation of smartphones why are there no attempts (if any) to go directly against Visa and MC? Is there really a need for the intermediate parties (payment processing systems) to exist? Visa will not let go off that model as it built that ecosystem over many years. So it really cannot compete on price if some one really cut all the middle men and comes up with a payment system + processing system. I am surprised that even the highly successful Paypal just feeds off of Visa and MC. I know the existing hardware installed at all the stores is a big barrier to entry but still.