I'm inclined to be less literal-minded about that stuff, but then again, I also grew up on comic books and old monster movies so the idea that "canon" does not faze me. Yet I'm not convinced that not being certified 100% "Prime" would somehow invalidate a new STAR TREK series or discourage people from rewatching it.
People still watch the classic old James Bond movies, even though that series takes a rather laissez-faire approach to continuity. People still watch the old Hammer "Dracula" movies even though they're barely consistent with each other.
If the shows are fun and entertaining and compelling to watch, being labeled "Prime" or not shouldn't make any difference. And, conversely, just being "Prime" or "canon" doesn't make a Trek story more watchable, all other things being equal.
"Turnabout Intruder" and "The Alternative Factor" are 100% Prime. Doesn't mean I want to watch them anytime soon.