Honestly a very few people would make a 100% switch from paypal to bitcoin, no matter the number of stores accepting bitcoin and no matter what the fees are. Buyers don't pay the fees, the sellers do. And there is no buyer protection with bitcoin, in the opposite of paypal
PayPal has a few major advantages that Bitcoin can't offer at this point;
1) Massive global acceptance.
2) Buyers protection.
3) Instant transactions when using PayPal balance.
4) No exposure to volatility.
In order for Bitcoin to interest PayPal users to at least partly ditch that service, Bitcoin must offer an equal level of world wide acceptance, and ease of use. Bitcoin at this point can't serve people in that regard. As long as that isn't the case, there is no reason for these people to hop over to Bitcoin. That's why I badly hope that Segwit and Lightning Network get implemented as soon as possible. It won't suddenly make Bitcoin superior to fiat related payment platforms, but at least it has then a solid foundation to keep developing further.