NO... some Protestant churches have not been changing as you said.
Stated below is the doctrine that my "Protestant" church teaches. It is the same as it has taught since the reformation, when the Protestant church was separated from the Catholic church. And I challenge you to find one word of it that is not supported by God's word in the Holy Bible!
1. I believe in God the Father, Almighty, Maker of heaven and earth:
2. And in Jesus Christ, his only begotten Son, our Lord:
3. Who was conceived by the Holy Ghost, born of the Virgin Mary:
4. Suffered under Pontius Pilate; was crucified, dead and buried: He descended into hell:
5. The third day he rose again from the dead:
6. He ascended into heaven, and sits at the right hand of God the Father Almighty:
7. From thence he shall come to judge the quick and the dead:
8. I believe in the Holy Ghost:
9. I believe in the holy catholic church: the communion of saints:
10. The forgiveness of sins:
1l. The resurrection of the body:
12. And the life everlasting. Amen.
Identify your Protestant denomination and let us see if it teaches today the same as the original reformers. Of course then we would have to ask, which reformer: Luther, Calvin, Zwingli, etc.? The teaching of Protestantism, as a movement, has been anything but stable.