it's not $8000 a month, december is when the advertisement money is at its peak. in january is at it's lowest, according to TB it's down 75% this year, meaning for the same views he'd get $2k instead of $8k. judging by last year's example youtubers are making half as much money per month from january to about june-ish. it would be closer to $65-70k a year, and that's not even salary, but small business earning, different tax rates apply to that, I don't know if in the us it's more or less than personal earning tax so can't estimate on that