Is there a credible source for the costs of hosting? Wikipedia is listing similar ad revenues as you did but no info on the costs. YouTube has 2.7 billion users that watch in average around 11 hours of videos a month. If 2 billion USD/y would be sufficient to host all that that’d be just 0,74 USD/user*year or 0,06 USD per month. That sounds really cheap considering that you have to pay for storage, traffic, backups and redundancies (at least I never heard of significant outages or data loss on YT).
Does anyone have a credible source on the number of employees YouTube has? If you search for that you fine vastly different number from just 2k to 189k employees.
Amazing present for insert your own name here