But nowadays only Ethereum have great experience of working with other altcoins, smart-contracts and problem solving. So, no matter what other project and experts say, today we haven't got any alternative for Ethereum.
P.S: Ether blockchain isn't ideal, but its team have already solved a lot of problems, and would do it again and again.
This is exactly the reason that you cannot compare Ethereum with bitcoin,bitcoin is a stand alone currency but ethereum does need new projects coming out on a regular basis to get the ball running and even if you compare ten years time none of the alt coins will be able to compete with bitcoin when it comes to market penetration.