I have no doubt that Bitcoin will be replaced in the medium term. It's unique selling point was that it solved the disadvantages of centralisation and was private. In practice it's very bad at both for most.
It's not pulling away from the competition either despite global exposure and massive investment this year it's down and struggling.
It's pulling away in terms of adoption and therefore usefulness. Not altcoins are making significant progress in adoption, but Bitcoin has important new announcements every week. (The entire crypto space is currently down, lead by Bitcoin's decline price decline.)
Atm BTSX isn't a competitor as it's still new and in rapid development and is currently more CPOS than DPOS. + I guess they need the same merchant, PayPal type access as Bitcoin. But in general they're developing so fast that it's a few months away from changing everything.
I doubt that PayPal is going to add support for 5 different cryptocurrencies. Adding even 1 more is probably well more than a few months away. No altcoins are making significant strides in mainstream adoption. Bitcoin widens the gap everyday.
Isn't PayPal partnered with Bitcoin payment processors so that people that use PayPal can also use Bitcoin?
Exactly, they are partnered with Bitcoin payment processors, NOT BITCOIN. PayPal will accept multiple cryptocurrencies as long as the payment processors handle everything for them. I doubt PayPal will even touch cryptocurrencies... The payment processors will exchange everything into FIAT for them. So, if BTSX can get added to one of the major payment processors it has a good chance to be used at PayPal and other major retailers. Getting added to major exchanges and payment processors is the key, as these major retailers don't give two craps about Cryptocoins. All they care about is money (FIAT), and cryptocoins are just another avenue for them to receive more of it.
To make getting accepted at a major payment processor more likely, BTSX needs to get added to older and more reputable exchanges (no offense to those that already accept BTSX). We as a community should focus on getting added to major exchanges and payment processors, and that will give us a good chance to be used at major retailers. Any cryptocurrency their partners support will be the ones that they accept, as they will be receiving FIAT no matter what cryptocurrency the payment processors accept.
Ps: see the link in my signature for things you can do to help that process.