There are, no doubt, many reasons. I would cite the number one cause is leaving the Word of God. Faith has as its origin the Word of God (Rom. 10:17). Speaking of faith in this way calls for effort on the part of man to understand what God’s Word teaches. It is not just understanding what God has said but it is likewise required that men do what God requires. Naaman would have died of leprosy no matter what he believed (II Kings 5). Proper faith as in his case was when he went to Jordan and dipped seven times. He was cured by God based on his obedience to what God had revealed to him through Elisha.
A close connection to that is men will work to change existing law. More times than not it turns up in worship. Men elevate themselves above what God has revealed and produce worship that is unacceptable to God (I Cor. 4:6; Matt. 15:9). This production comes about because men are trying to please themselves and not God in their public worship. It can also manifest itself in men thinking they know more than God. They hide behind “culture” or that the scriptures are not “relevant” for our times. They act like God does not know what is best for the church. Once you leave a thus saith the Lord, man must elevate himself to make decisions about direction and content of the souls of men (II John 9).
A mistake that can take place is that people believe that as long as they worship and there is no disturbance of any kind, they can go about living their lives the way they want. Worship is accepted by God from those who serve and obey God (Acts 10:35). There is nothing wrong with change. However when it is change for the sake of change, the church will suffer. People who charge the church with serving traditions always call for a different action. The action called for is always that which is not authorized by God. When there is a call for change, check the motivation. Churches change not because God has but because they have (Malachi 3:6).