Bitcoin is not competing with PayPal or Visa its competing with the US dollar. So in a sense the relationship between Bitcoin and Paypal is like the Trojan horse and Troy. If we get bitcoin inside PayPal, then that will be a big blow to the US dollar. For the number of users, maybe yes. But for the entire thing, it won't be. Because Bitcoin and PayPal is a different thing, you can't just compare it because both of them are used on the internet. PayPal is an online payment system that using government's currency, but Bitcoin is the currency itself. So maybe many people will use Bitcoin, but PayPal won't die because people still need it somehow.