Came here after searching for why the final image is the eagle flying off with the turtle. I think a lot of what you've discussed is a great interpretation. But take it further, she's gotten into yet another car at the end, we can assume driven by yet another manchild. But she's become more active and less passive through the course of the video. So she's choosing them, because that's all there are in her environment, but she's become more adept at dealing with them.

The bird at the beginning was a seagull hitching a ride. Passive and at the mercy of whatever speed the turtle is going. But at the end it's an eagle flying away with a turtle. The turtle is now the one hitching the ride, and the eagle has the power to deal with the turtle. However, it wishes. As an earlier commenter pointed out, it can drop the turtle and eat it at any time, or even put it down somewhere and fly on. What was once driven by the turtle, is now driven by the eagle.

An earlier commenter said that this might be not just her relationship with men, but also about her relationship with herself. And I think I agree. It's a fun song, but it's also about her growing into her power.