I am also a trained Engineer and have a PE and I have absolutely no clue what the OP is trying to describe. If his quill stem is held in place only by friction as you surmise he has a disaster looking for a place to happen. Also, I have no idea why he things changing the crank and bottom bracket will have any influence on this.

Troll? I dunno but it has some of the earmarks. If it's a serious posting that may be even worse.