Sadly, not in my experience.
And I am not part of a mainline denomination.
Biblical acumen among Christians is horrifyingly pathetic and the churches that are growing are your Joel Osteenish Health/Wealth/Prosperity-pushers.
While I don't exactly disagree, the article speaks against that - And some of that must be true. I know the Presby USA church here is 1/4 full of old liberals, but the Presby OPC church here is packed to the rafters and completely out of room, full to overflowing with young families and children.
Same with hardline Baptist... Heavy presence, big, young churches.
I will agree that Non-denom Evangelicals seem less trained up in the word - been critical of that for a while... It is fair to say that praise churches, which nondenom evangelicals around here seem to be, tend to be Biblically ignorant. But that is subjective in itself - Like trying to track Baptists, because they are congregational, and don't have much hierarchical order, my statement is hard to prove true in individual churches.