It could be argued that YC wouldn't be as popular as it is today without HN. Also it seems to be a great recruiting source for YC companies. It doesn't have to

It could be argued that YC wouldn't be as popular as it is today without HN. Also it seems to be a great recruiting source for YC companies. It doesn't have to literally bring in money to be considered profitable when the profits could be in the form of more intangible things.