Not to say that the "flippening" couldn't happen, but I think 3 issues would hold it back ("B" is exclusive the ETH though):
A) Scaling Issues.
The second people start using it for more "regular" transactions it'll run into the same scaling issues as Bitcoin has.
B) Smart Contract "Pollution"
Every smart contract is stored in the Blockchain. As the number of them grow the ETH blockchain will get huge, and way to big for most hobbyists to run a node.
C) Adoption
There is a growing number of places accepting Bitcoin, and I heard that about 30% of Bitcoin transactions are purchase related (the other 70% being speculation). You really can't say that about any other crypto though, so it'd be hard to get that going.