One trend we're seeing a lot of is regulation. China clamped down, Korea is threatening to clamp down... those of us in NY and WA are already dealing with this; if you want to trade crypto, you have to trade in a house that's FDIC insured. It has to act like a bank, look like a bank, be regulated like a bank and have reserves like a bank.
That means Gemini.
And Gemini deals in BTC and ETH, and that's it. There may be other firms willing to step up to the requirements necessary but as other states clamp down on crypto (which they will do, the first time anybody loses their home or some shit because of speculating on BTC futures), it's gonna close out a lot of the weirder coins.
One thing about BTC and ETH - it's not that hard to move around without an exchange. But for everything else, it's gonna be exchange exchange exchange. Even now most of the transactions aren't wallet-to-wallet, they're internal exchange.