Yes Star Trek TOS went into a tailspin in its last season. The worst episode being the one about the space hippies! I can’t remember if that was in the last season or not but it was an absolute stinker! I still refuse to watch it.
Ironically, the space hippies episode has proven to be prophetic.
His problem was being born and raised in the sterile environment of a space ship, he could never visit a real planet, because he was allergic to everything.
Every wonder why allergies (like to peanuts) are common today, yet were rare 50 years ago?
"Enterprise's" last season was a real stinker. It actually showed some promise early on.
Mark