If HN fails to ever hit 1M users, PG (or Sam Altman) isn’t going to shut it down or cut off its funding, and neither he nor Y Combinator are expecting or relying on it to generate revenue. It continues to exist after over a decade because the Y Combinator folks find the content and discussion interesting.
And hey, that’s all well and good. I’m glad that HN sticks around when a more profit-driven site would’ve failed years ago. But it’s important to note that what works for HN likely wouldn’t work for anyone else.