BTC Tx volume will hit a wall eventually as the transaction fees are highest among all cryptos. XRP has some of the lowest fees and bankers use it. So that's expected. ETH was never meant to be a Cash Alternative.

In few years time the volume will favor Dash and NEM more and more.
I heard IOTA has no fees. Yes, zero Tx cost. I'm looking forward to see how that would turn out to be.