I don't think Mycelium has enough users when compared to Blockchain.info. IMHO:
Isn't that like saying the World only needs one search Engine since most people use Google?
Or, ummm, we only need Internet explorer since it was the first and most people use it?
As for me, I am happy that Firefox and Chrome came out even though IE was first.
As for me, I am very happy that Comcast cable came out. With your logic, I would still be stuck on AOL and dialup.
Yes, blockchain.info is nice, but it's still a webwallet. MyCelium is iOS and Android. I don't have to worry about my computer being hacked with a keylogger to use Mycelium.