You don't need humans to moderate the "500 hours of video uploaded to Youtube every minute". Most of those videos get little to no views and are irrelevant, and then most cases of infringement are clear cut enough that automation can deal with them. Most people don't bother to appeal.

The number of cases that actually need manual moderation would be many orders of magnitude smaller.

Imagine a system that works something like the following:

- Users get access to manual dispute resolution by proving their real identity

- Persons with enough obvious violations (i.e. outright piracy with no possible argument of fair use) are barred from the dispute process

- All disputes get sent to human moderators and handled within 24 hours

- There are multiple levels of appeals, starting at appeals to unskilled laborers and ending at appeals to experienced copyright attorneys

- Going to higher levels of appeals requires paying in a nominal fee that is returned if the claim is overturned

- The final level of appeals can decide the case is too unclear and should be handled by the courts as per the DMCA

- Claimants are penalized some nominal fee for overturned claims

How many moderators would that need? It'd be 1,000 at most. Majority of them would be outsourced laborers costing around $20-30k, with a few experienced attorneys costing $200-300k for the final stage of appeals. Total cost $20-30M. That's a lot of money, but still only 0.5% of their actual revenue. Such a system would surely create far more value both to the company and to the world.