Why "home inspections" and "inspectors" are complete horseshit

This is a tale. Unfortunately it ain't a tall tale, but a big pain in the tail. I had a wall that was messed up. Home inspector didn't catch it (which leads me to believe that "home inspections" and "inspectors" are bullshit). So I am having to fix a wall with rot. Can't get asbestos tiles anymore (eco nazis) so I had to go with Hardy Board (I am sure cutting it will give me silicosis quicker than the non-friable asbestos tiles will give me mesothelimoa). Since the house is 70 years old and settling, none of the angles line up right. I am convinced that Christopher Wren would have a hard time making it right. Oh and btw, I refuse to shell out more than $2k for some so-called handyman to do only a marginally better job than I will...