I think once Bitcoin is big enough and becomes more stable it has the potential to overcome Paypal. Once outside people start to realize the potential of Bitcoin they will see it more as a currency and be able to treat it like one also.
Definitely yes, bitcoin could surpass paypal. Yeah, it is indeed that bitcoin is not popular yet. But bitcoin has a potential that paypal doesn't have and it is "voltality" this means that bitcoin could grow into enormous value but also fall. The only advantages of paypal is, it is legalize and widely used around the world but if bitcoin has been acknowledge by everyone I'm pretty sure that they would choose btc instead of paypal.