How is their fault? There's no indication they ever saw the original scoop since apparently nobody did. Newsday is the main paper for Long Island and they didn't pick it up either.
The beat of the “All the News That's Fit to Print” New York Times does not include Long Island? NEW YORK Times? Are we talking about the same publication?
In this case, it was a house race. There are 435 such races. It would surely be great if the Times would vet all 870 major party candidate for us, but in practice that's not feasible given their revenue structure. We need to rely on local journalism like the linked coverage of the North Shore Leader.
And as it happened, they did their jobs. But none of us were listening because, collectively, no one gave much thought to a house race in a left-leaning district in a deep blue state. The whole thing blew up only because Santos (somewhat surprisingly) won his race.
It has a local paper, not the North Shore Leader, but Newsday. Newsday has a weekly circulation of 1 million and has won numerous Pulitzers.
The massive failure here is on them and it should prompt some real soul searching.
Having said that, even Santos' opponent did a terrible job of campaigning against him, despite the fact that he's president of a PR firm. He was on Twitter the other day trying to look tough and demanding a rematch until being shamed into silence by his own increasingly-former supporters.