Again, Youtube splits ad revenue 55% to the creator and keeps 45% for themselves. The $4 per 1000 views number I am stating is the money advertisers are paying Youtube unless the term “net revenue” they are using in their revenue sharing FAQ does not mean the the incoming revenue from the ads. I am fairly certain that if they were deducting their cost of delivery from that number then net revenue would not be a correct term and they would need to disclose it as gross profit or some other non-revenue term. As a result, I believe my statement that Youtube is getting ~$4 per 1000 views from advertisers is a accurate representation of the information I have presented.
You've skipped paying additional rightsholders - subscription music rights are substantively more expensive than advertising funded ones. You've no processing fees.