Even with the cost of health insurance for over 66's I believe cost of living here
can be considerably cheaper than the US. It depends on how you are living.
If you are 66+ you're probably not buying a lot of clothes - those can be expensive here.
You can buy an apartment in non touristy area outright for the equivalent of the 15% deposit down payment in the USA. If you want a penthouse in Recoleta or Palermo or Puerto Madero then expect to pay the same as USA or more.
I see posts on this forum about people quoting 200 pesos u$s70 per person for a meal as reasonable? If you want to eat in upscale / expat tourist traps then NO you're money won't go further than in say Florida USA.
If you're prepared to explore a little and ask the locals then the quality is just as good and often much better at a fraction of the cost. My rule of thumb is if the menu says Bife de Lomo for more than a$32 pesos - walk on by!
Lunch - Menu Ejecutivo costs a$22peso in several restaurants in Puerto Madero (a bling bling neighbourhood) incl main course a drink and desert or coffee. - you can buy a coffee and little else for that price in New York
I've lived in London and New york but my groceries here are a fraction of what I paid in those cities.
Electronics are expensive here but just bring those with you.
go and visit
Soulskiers turf in Bariloche - you will never see scenery quite like it anywhere else!