Pseudonym said:
To the best of my knowledge youtube itself has never been profitable, though it is hard to factor in the way it helps google with certain types of data collection. Now I don't have any pity for google or youtube, especially since they have encouraged and set up a system where many people are dependent on youtube for their income. In my opinion that means you have certain responsibilities even if you aren't legally their employer.
Well, the Wall Street Journal apparently reported that it was not making a profit in 2015, with revenue of 4 billion approx.
However, since then, it has not been reporting its revenue, profit, or much else, so we cannot tell. But from what I can tell from a quick search, its revenue is likely to be several times higher.
Still, even if not, they're under Google's umbrella. The costs of running the service are perfectly manageable for them.