I wouldn't be surprised if RIPPLE beats Bitcoin as well because of the cheaper transaction fees and very fast time it takes to do the transactions. If the banks all get behind Ripple technology then this is what is going to have the biggest marketcap dominance over the coming years. Bitcoin will lose it's top position if RIPPLE goes up another five times and Bitcoin keeps declining in price. If XRP beat ETH, then it will beat Bitcoin marketcap too I guess in 2018 or beyond.
Realistically, your analyses are feasible, any coin can come from behind to take the number one position, i wasn't expecting ripple will upstage etherum any time soon if this can be done against etherum why can't the same be done against bitcoin.