Sorry, but I disagree with you on this one. I was recently on a dive boat in Cozumel where one of the divers hired a private guide. It had been several years since she had been diving and didn't want to hoard all the dive master's attention. She wanted to feel comfortable, especially with the currents, before being more self sufficient. I would rather have a fellow diver somewhat uncertain of their skill level versus one who is cavalier and over confident( definitely not referring to you, but I am sure you have also witnessed these traits). I have seen disasters with the latter. While my husband and I shore dive in Curacao without a guide, I find it occasionally beneficial to find a guide who knows where to find the frogfish, seahorses etc. plus knows the reefs like the back of their hand.
As I am getting older, and dealing with the travails of finding the correct balance with distance and reading correction with contact lenses, the extra set of eyes make the dive more rewarding.