That is possible but extremely unlikely. Companies who spend interesting amounts of money on advertising don't just hand you $100k or something. Instead, they

That is possible but extremely unlikely. Companies who spend interesting amounts of money on advertising don't just hand you $100k or something. Instead, they hand you $10k for a month or a quarter and tell you to demonstrate what you can do. You only get more as long as you can show something going up and to the right. So you can certainly get to million dollar accounts but it's going to take at least a year of demonstrating performance and going out and demanding quarterly increases in spend. Now, to your claim: could fb get $2B in ad spend w/o demonstrating that performance? Sure. It's damn unlikely though because the companies that will eventually spend $1m/year with you don't start there. If your theory is there is super high churn, then 2e9/(10k) = 200k different advertisers spending $10k for a quarter then churning. That seems dubious. Now obviously they make some money from tax, etc, but just look at the rough order of magnitude of new suckers you would have to find every year and estimate whether it's likely.