RBS launches mobile number-based P2P payments service

How come that card schemes are unable to build a real time P2P service supported by mobile phones?. They have the authorisation message in real time that could be used to withdraw and deposit in payer and payee card accounts, the original credit transaction, global reach through 28 000 banks in +180 countries, operating regulations, business model (atm withdrawal), mobile wallets in the making and experience in the area. Electronic P2P in real time is a real customer need for payments between consumers. Instead they focus on mobile wallet payments in F2F merchant outlets that already accept cards with chip and PIN?  Why would I at Sainsbury´s check-out lane dabble with my mobile phone when I can stick in the card and do my four digits?In addition to this they approve Squares and iZettles where consumers should act as merchants making a P2P very combersome. When I sell my son´s old bike to a stranger I would like to receive an on-line P2P instead of 50 GBP in cash and he would like to pay only when he gets the bike... Card schemes should focus on unmet customer needs instead of fixing what is not broken.    

@FinextraM: Very simple answer: There's no interchange fee in realtime P2P the way Barclays or RBS are doing it. Visa did try web-based realtime P2P between Visa cardholders a few years ago. Not sure if the service is still available but they did attract a big furore at the time when it was rumored that they'd start charging interchange and cash withdrawal fees on these transactions.