- The vast majority of projects helped by NEA/H funding don't go on to Hamilton-size success. There's no way, years before the fact, for grant-giving organizations to look at projects and say "nah, you're going to be rolling in it soon, you don't need our money now."
- The ones that do are actually an incredible argument FOR the small dollar amounts of help that the endowments provide in the early stages, since the economic benefits are a huge return on a tiny investment. In two years of runaway success, Hamilton has surely enriched the federal treasury by many times the original grant that helped it (which also helped a dozen other shows that haven't taken off).
And the LA Times piece linked was more of a quickie "what do these things do?," which calls more for high-profile examples of work that benefited. If you're trying to define them in a hundred or so words, you're not going to make it if you start focusing on the small, local organizations unknown to your readers to which small (to the government) checks are a big deal.