Paypal is smart they will survive somehow.
Paypal will be history in 5 years. It took them about that long to get to mass adoption...so bitcoin would take less time to go mainstream and do it better. Paypal can't compete with bitcoin. They might offer a wallet service but the second people learn enough about bitcoin they will not put their coin in paypal unless they're stupid.
They can't offer anything to outdo bitcoin, neither in service, currency and certainly not security.
It's the difference between a corporation selling bottled water or confiscating it at a whim, and everyone having their own well spring in their back yard with lifetime pure water. Only an idiot would buy from the corporation.
Western Union though will fall before paypal simply because online is more convenient than offline. Once people understand they can send money instantly for pennies, online, they will never step foot inside another WU.
Soon as the infrastructure is in place and the transition is smooth, mass adoption will escalate and these two will begin to implode as people leave them or stop using them in droves.