"Their own ends" being...what? Telling a fun story? How many times did TOS alter its own continuity for the same reason, or for no reason at all? Tell you what, let's ask James R. Kirk. You know, the captain of the United Earth vessel Enterprise? The one that's 900 years in the future, according to "The Squire of Gothos"? It was launched under the auspices of the United Earth Space Probe Agency, I believe, and it had a Vulcanian science officer named Spock who laughed out loud when he saw weird flowers. That's totally different, by the way, from the "space vehicle Enterprise," the one that Captain Pike commanded.
Exactly. The only real Star Trek is "The Cage." Everything is a bullshit cash-in that betrays Gene's vision.