I'm thinking that if you sent a dozen people to Alpha Centari, it wouldn't make any difference because that is under the threshold of people that would be required to establish a self-sustaining colony that, in turn, sends out similar expeditions in the future.

Do that sort of stunt as much as you like, it won't become something more. It's like trying to jump over a building by hopping a bunch. You can hop one time or one billion times, you won't clear the building because after each failed hop you're back to square one.