7k transactions per sec with zero fee.
Thats for sure, it is designed from the ground up for that, it has been proven to be not be affected by the number of transaction that are being performed by the network at the same time.
Can it reach $1000 by Dec 2018?
Well that will require a massive growth but it will reach it bit by at least dec 2019: it has no inflation at all (there will never be more than 133,248,289 XRB XRB) and has a unique Blockchain that provide what we forever wanted.
Can it beat Ethereum and Bitcoin?
That will depend on how much those 2 keep growing, but if (mainly Bitcoin) stay #1 it will be bad for crypto altogether because this one doesn't bring what we want.
So hoepfully RaiBlocks will be #1 at some point.