If you think Playa's bad, you should go to Cancun. Talk about a ripoff, I remember when it was a budget traveller's destination and Playa was still "off the beaten path".
I feel your pain, but I have to say this- stay away from the tourist places. I know you already know this. Like airports, they charge these prices because they can, pure and simple. Eat where the locals eat and you'll save a bundle. That meal at Johnny Rockets would have cost you half that or less at a little hole-in-wall restaurant off 5th Ave. Likewise, that ice cream at Haagen Daas would cost you about 10 pesos from a street vendor and probably be just as good or better. I'm afraid that prices are just going to keep going up in Playa, at least in the immediate future.