I honestly don't like the term "don't let perfect be the enemy of good", and it's from what I'm going to call "Zeno's compromise". Basically, someone who wants to do nothing will always meet you "halfway" between you and a solution, which basically means you'll never reach that solution. I also believe this is the underlying reason for the "liberal ratchet".

Instead, I think of it as "a long journey begins with a single step". You cannot ensure you will reach the destination if you never actually leave.