TOS is hard science fiction.
What are you on?? TOS is campy space adventure. Kirk vs. Apollo. Kirk vs. Klingons. Enterprise invaded by space hippies. Spock's brain is stolen. Nazi planet. Roman planet. Spock's Vulcan mating urge means he has to fight Kirk to the death. A giant space amoeba threatens the galaxy.
I LOVE TOS, and a few episodes had big ideas, but let's be realistic, eh?
TOS focused on actual science fiction concepts while the later Treks used science fiction merely as a backdrop. TOS was actually about exploring strange new worlds and seeking our new life, but TNG just used that in its opening title sequence. No, TOS isn't the hardest of the hard, but I would describe it as hard science fiction relative to the other series. I've read several posts from TOS (and early TNG) fans saying that they enjoyed TOS because of the strange new worlds and wacky sci-fi concepts while the later series became soap operas. The science fiction element of TOS is a big appeal of the series.
Anyway, you're taking my tongue-in-cheek 5 word summations too seriously. Would you believe I don't like TOS and actually enjoy Star Trek "is shit" Enterprise? But hey, if you can come up with a better summation for TOS that is 5 words or less (not counting the is) I'd be happy to change it.
If any of you are true Trek fans, you will like every series.
Worst logic ever.