I think it's simply a matter of lifestyle preference and who they're catering too. Personally, I stayed out at Sonoran Spa last January and was not pleased. It was HUGE and mostly empty and I felt stranded. I'd never buy a condo out there because they price is stupid. I usually go down with a large group of people and we like staying in town so we all stay at PDS because it's small comparatively, reasonably priced and has a great pool in a perfect location.
That said, there are a lot of folks out there that want their home away from home in Mexico in a place that doesn't seem like it's in Mexico. From what I can tell, there are a lot of baby boomers who own and rent to the younger generation because, frankly, we're spoild brats who want everything fancy and pretty and are willing to pay for it. We're overconsumers.
The HOA fees tie directly into that. They're high because you have a significant amount of amenities, infrastructure and staff to pay for. But, you know, those weekend renters don't want to see dead plants or crap on the beach. I run a very large HOA in AZ and I'll tell you I have people complain about the cost of the HOA but then the same people call me demanding additional services and not realizing it has a cost involved...