I think a lot of the people who might traditionally have been the target market for dishwashers already have one... The Argentine word is 'mucama.'
As the prevalence of staff decreases, I imagine that dishwashers will become more common. But they haven't been provisioned for in most kitchens so it will take some time.
I think you might be on to something. Kitchens don't have dishwasher hookups but even new constructions (in nicer areas) have dependencias.
I'm completely with you on the clothes dryer; this drip dry BS is for the birds. But I'd like to hear what you perceive to be the argument in favor of a dishwasher. I actually have one, but haven't been using it.
Convenience? Leave and forget? Cleans better, no spots, blah blah blah. I always compare a dishwasher to washing machines, both are expensive complicated appliances that take 10 times longer to do what would be a relatively simple manual task, one that people have been doing for millennia.
But if you use dishwashers (and washing machines and cloths dryers), you manage to, with a relatively small in investment, you suddenly free up hours and hours and hours of time which was previously dedicated to tedious mindless never ending chores.
Now if only they'd come out with a domestic automated shirt ironer, I could finally upgrade from my current 'mucama' model.
Edit: A high quality properly set up dishwasher cleans way more effectively than I do. Especially wine glasses, thats the place where spots and drips are most frequently noticed and I struggled to get mine clean before having the dishwasher, now they shine! Not to mention, as of last night, I've lost 3 fine wine glasses to my dishwasher (each broken during my brutish loading or unloading, never during the wash cycle) in the last year. That pales in comparison to the 30+ I lost during the manual cleaning process in the 4 preceding years. It's apparently illegal to make crystal wine glasses in Argentina so we're stuck paying through the nose for imported Czech stuff or stuck with the worlds most fragile Nac&Pop. With my troll hands, the dishwasher has probably paid for itself in wine glasses.