While I don't think anyone would argue that we are testing anything approaching "enough" people in the US, I would certainly not say we're testing "almost nobody". Looking at Politico's testing tracker (
https://www.politico.com/interactives/2020/coronavirus-testi... ), most states outside of the hotspots in the Northeastern US have administered about 10x as many tests as they have positive cases.
New York and the surrounding areas are obviously a different matter, but at this stage I suspect that even if they did have enough physical tests and capacity to process them they would not have anywhere near enough medical staff to physically administer them. There's also the tradeoff that asking hundreds of thousands of people to leave their dwellings to seek testing would do more harm than good in areas where that necessarily involves walking, public transportation, etc.