The reason for this is that Ixtapa was never a real town, but a location picked out by the Mexican tourism agency to develop into resorts. The beach is packed, Miami-like, with ugly high-rise hotel properties, and there are the usual shopping malls and tourist restaurants to visit (and no, in my opinion Señor Frog's is not an authentic cultural experience). The golf courses aren't particularly good, nor is the diving, and if you want a decent octopus taco, you need to get in a cab and drive to Zihuatanejo, about twenty miles to the south.
The one cool thing to do in Ixtapa, in my experience, is to head out to little Isla Ixtapa, a gumdrop of an island, a quarter-mile or so from the shore, that you reach via private transfers from the dock at Playa Quieta beach. There you'll find a scattering of restaurants lined up on the sand that will happily grill you up a slipper lobster or a huachinango red snapper, and keep the Coronas and margaritas coming until you say, "No mas." The water is warm and sandy, the snorkeling is pretty good and there are four beaches to explore and stroll, with different views and people-watching scenes.
Touristy, yes, but I liked it because when I was there, a Mexican family parked themselves in the sand near my rented beach chair, produced food and tequila and salt and limes for the grown-ups and toys for the kids, and chatted the afternoon away while the kids played in the sand and sang the Power Rangers theme song in Spanish.
Now that was an authentic cultural experience, and the next time that I visit Club Med Ixtapa, I'll make a point of spending an afternoon back on Isla Ixtapa.