Read all about it at The Gospel Coalition. BTW, I think it’s a great question!
The midpoint of my arc from Catholicism through Evangelical Anglicanism and back to Catholicism came when a Reformed friend asked me to read Piper’s Desiring God…and I bounced. It was the first time I’d really come to grips with Reformed Theology, and I just couldn’t make myself believe it.
I am certainly not learned in this, so take this observation for what it’s worth. The reason that I think that Evangelical Protestantism has taken over the US protestant world is because they have reduced Christianity down to a hand full of simple precepts: All you need to do is profess a faith in Jesus and read your bible, and you can interpret the bible in almost any way that inspires you. Christian theology in its fullness is actually pretty complicated in comparison to the other world religions. Catholicism and most mainline Christianity are very complicated. That’s why so many Catholics don’t know their own religion. Like most things in life, simplicity rules the day.
Other religions are pretty complicated too. If you look at the fullness of Hindu or Buddhist thought, it is very complicated.
They are coming from La Mirada.
My own take – A lot of Evangelicals are sick of what looks like anemic, unintellectual, ahistorical, touchy feely nonsense, and even if the Calvinistic brand of Evangelicalism is mistaken, it’s certainly none of those things.