I would need over 80k views a day to make me even "think" about leaving my current job to do only YouTube. Remember you need to make more than what you would at a company, because you are not getting 401k benefits, and will probably pay more for dental, health, etc.
@ $3.00 RPM per 1k views
80k views a day x $3.00
$240.00 a day - network cut (minus $60.00 as an example)
$180 a day x 7 days a week = $1260.00
$1260.00 x 4 = $5040.00 a month
$5040 x 12 = $60480.00 a year
YouTube fluctuates and you may even get higher RPM or even lower RPM each month, so you have to account for that. You also have to account that you won't always get 80k views a day, but may get 30k one day, and 50k the next.
If you make 40k a year at a company, you should aim for 60-70k before thinking of YouTube as your only source of income to account for any YouTube fluctuations.