Probably Ricardo has more dignity than Alberto the Traitor and won't sell himself and his race for money.
No disrespect to Ricardo but if WWE offered him half the money he was getting before and a year supply of JR's BBQ sauce..I think Ricardo would jump at the chance to come back to WWE. He may say he's a proud guy and all this other stuff but he's not crazy, if WWE called him tomorrow he would be licking their boots to be back in the company.
From all accounts Ricardo loved being in WWE and he just felt he was underutilized. I know Zeb and Alberto have only teamed for a few days but I'm already not buying this pairing, I think Ricardo was truly a perfect foil for Alberto much like Heyman is to Brock. I'll give Zeb and Alberto a chance but it doesn't seem to be working on any level right now.