It should be a minimum commission of 10% atleast to make exchange with your paypal funds.
Bitcoin value is growing more and more, so no one will opt to loose such a profitable coin at this paltry 4%
Another reason no one will sell you bitcoins is that there is no guarantee that you will not do a chargeback on those paypal funds you sent out because you have no trust here.
There are plenty of trusted members also offering paypal for bitcoins and I am sure people will just buy from them.