As an ex-vangelical, I have to partially agree with you. One of the reasons I left the faith was that I had no idea about the sacrifice expected of believers. But this wasn't my fault. I was not raised in church. I was sold a "free gift of salvation," as a freshman in college. https://medium.com/interfaith-now/mission-2000-how-i-lost-my-faith-in-a-push-to-evangelize-the-globe-13abffaa3782
Nothing was said about discipleship or what it meant to "lose your life for my sake." If this honesty had been presented up front, I would most likely have said no from the outset. You can't blame people for bugging out of the faith once this becomes clear. You need to be honest with them up front.