First of all, a link to reddit isnt an acceptable source. Second if it was common knowledge that YouTube ran at a loss I would think looking up “does YouTube run at a loss” would give something more recent then 2009 I did find this from 2016, by looking for “YouTube revenue report” and according to this YouTube generated 31bn USD in 2023, unfortunately I can’t find any concrete numbers for operating costs but some estimates I read were between a couple hundred mil to a few bn, either way drops in the bucket compared to profits. Sure YouTube may have operated at a loss at first but its highly unlikely it still is.
A reddit post from 8 years ago is not going to have up to date information so no, not a valid source, but even in that reddit post many people point out that youtube was breaking even in 2014 not operating at a loss and I find it highly unlikely that the growing YouTube would still be breaking even a decade later. I did read the reddit post and the sources they provide require subscriptions to access. This will be the last I respond to this though since I can’t see this going anywhere, continuing the conversation would be asinine.