Does it? Alphabet quarterly reports don't list YouTube revenues and expenses separately, and i imagine something like YouTube costs a shit load of money in storage and bandwidth.
Technically (and by accident) what I originally said is still true— it makes a lot of money (but may cost a lot of money) and so it still looks good on quarterly reports (esp. if they bury the costs) so they’ll keep it around.
Plus, I wouldn’t be surprised if my Google search results were informed and improved by their data about my watch history.