Paypal cannot be overcome by bitcoins because of the simple reason that 90% of the online e-commerce sites accept paypal as a payment method and hence that plays a vital role. Though a person who knows btc and paypal both would always prefer dealing via bitcoins.
It's because of united states influence over PayPal with international corporates. If PayPal can acquire this place without having ground features bitcoin, then why can't bitcoin to achieve that place. Just silent and notice what will be happen in 5 years, 90% site will accept bitcoin.