It's not a failure - it was the best that we had for centuries. We have better translations now. Nearly every evangelical scholar believes this. Nobody is talking about casting Scripture aside. We just prefer to use modern translations that are rendered from more reliable consensus of original sources.
The language isn't confusing at every point, but let's face it, meanings of words change. The archaic usages are completely lost on an uninformed reader, which most of us are when we read the KJV text with a nuda scriptura approach. It's not a convenient excuse for getting rid of it and I've never heard of anyone who believes that. Some, I'm sure, use other translations because they prefer them, but it doesn't change the fact that the general consensus.
I know there are pockets of people who still prefer the KJV, mostly in non-SBC Baptist circles, but this is just not the case. Check out the best in evangelical scholarship today. Check out scholarly journals and other volumes. When they're not using Greek and Hebrew texts, they are using NIV, NASB, NRSV, ESV, and other modern ones.
I'm not knocking the KJV. It is the version through which many were led to Christ and it served the english-speaking Church faithfully, but there are more primary sources available now and more informed scholarship.