In order to work you need paypal accounts with a long history, otherwise the money goes on hold very quickly.
Old accounts cost a lot. Depending on how long an account lasts, it can be profitable or not.
If you pay 300 usd for a good account and it holds out for 3000 usd, that means that for every 3000 usd you collect you lose 300 usd to process the payments (+ paypal fees). That means a minimum 10% cost for processing the payments.
If you still have money blocked in that paypal, the loss is even bigger.