The top players right now (besides Monero and LTC) are all scam coins (ETH, DASH, Ripple, et. al.). A centralized, banker and corporation funded coin like ETH or a system (backed by the same groups) such as Ripple can easily overthrow the Bitcoin market cap within a week.
I agree. I also thought about it. Even if one of this coins surpasses BTC in marketcap, their fiat (ETH), scam (DASH), centralised trusted (Ripple) nature will become evident sooner or later. Unlike you I also disrespect LTC since it's a copycat.
ripple and dash wont go anywhere
but looking at how the 'merchant tools' and the VC's behind blockstream are also looking at ether and LTC and zcash. you can see they wont give up without a fight.
coinbase for instance can with a click of a button allow their hundreds of thousands of merchants accept LTC and ethereum as a payment method in shops that currently use coinbase merchant tools.
so although these alts are not as good as bitcoin. you can easily see blockstream devs jump over to most probably LTC if segwit gets adopted over there. especially with coblee at the helm of coinbase