The Christian life is about being and doing what the God in the Bible says to be and do. However, along the way, evangelicalism and fundamentalism has made it into what God doesn't say in the Bible to be and do. Those are often called liberties. The idea is that if the Bible doesn't say anything about it, then it is permissible. It is then neither wrong nor right. And so a lot of the agenda of churches ends up being other than what the Bible teaches either in proposition or by example.
The Bible is a relatively long book. It's got a lot in it. It has in it plenty to do. You could keep busy doing just what's in it. Jesus said we are sanctified by the truth and His Word is the truth (John 17:17). We can conclude that we are not sanctified by what isn't in the Bible. We can do things not in the Bible and those things will not sanctify us. The point isn't to find out what isn't in the Bible and then to do that. The goal should be to sort out what's in the Bible and do that. We don't have the liberty not to do what the Bible says. And when we are not doing what it says, then we are not doing what it says. We might not be doing something that it says not to do, and that's good, but that doesn't mean that not doing what it says is good. We are supposed to do what it says.
Ultimately, the reason churches have decided not to do what the Bible says is because the world doesn't like what the Bible says and churches know that. Because the world doesn't like it, what the Bible says also doesn't "work." The gospel of the Bible doesn't "work." The practice of the Bible doesn't "work." Because the Bible doesn't "work," what becomes practical for churches is what the Bible doesn't say. When the things not in the Bible do work it validates them to their users and advocates as somehow practical and therefore spiritual. God is "using them." And the more they work, the more people use them.
Depending on what isn't in the Bible is not living by faith. We live by faith when we follow what the Bible says. And faith is what pleases God.
So many of the methods and institutions used by churches are not in the Bible. These non-scriptural methods have become the evangelical and fundamentalist tradition. The traditions of evangelicalism and fundamentalism have become bigger than the Bible.
The main argument I have heard, besides that these traditions and non-scriptural methods and institutions "work," is something like, "well, we use computers and typewriters and those aren't in the Bible." The syllogism for this argument would read as the following: Computers and typewriters aren't in the Bible and we use them, computers and typewriters aren't wrong, therefore, all the things that we want to use that aren't in the Bible are also not wrong. I expect that one attack on this post will be that it is written on the internet, which isn't in the Bible.
Scripture does not say that it is wrong to play baseball for 15 hours a day. The Bible does not say that it is wrong to eat a gallon of ice cream every day. God's Word does not say that it is wrong to watch documentaries all day from morning until night. If the Bible doesn't say it's wrong, then it must be right.
God didn't say Cain couldn't bring fruits and vegetables, but when he did, God disrespected his offering. God didn't say that Israel couldn't worship God in Dan and Bethel or in the high places, so they did. We find out that God didn't like it. God wants what He said, not what He didn't say.
The churches that use these non-biblical methods are rewarded with congratulations and promotion from evangelicalism and fundamentalism. The people that use them write books about what they've done and people read and then emulate the books. Entire conferences are dedicated to the methods. The non-biblical institutions are attended and supported. There is a priority of what the Bible doesn't say.
And so we've got billions of dollars and decades of time spent on that which is not in the Bible. This is where we've got into trouble in Christianity. In the end, what is saddest is that God is not glorified through them. Men have been glorified and they have been glad to receive that glory and men have been glad to give that glory to them.