What I see is that the crypto currency has never been stable and never will. There may be some coins that will be used by people for payments such as hotels, meals or coffee. Even now there are already but if you are looking for coins that are stable in price it will be difficult, bitcoin that we often see has never been stable until now.
You can't compare bitcoin, ether, and other altcoins with stablecoins. They are completely different in purpose and the way they are designed.
All stablecoins are not the same by type (Fiat collateral, crypto collateral, non collateral/algorithm) but they are all striving to be stable in price. Most notable examples of price stable stablecoins are Tether and lately TrueUSD, but many more are emerging and it seems that the market is maturing and is finally ready to accept stablecoins.
Take a look at this article. You may find it useful -
https://medium.com/cp-processor/comprehensive-overview-of-stablecoins-819d183f6ac7