I'm forever hearing "it's never too late to change"; "life can be anything you want it to be"; "only you hold yourself back".
But just being realistic here - by the time you are in later middle age. Married with children and no good reason to leave your marriage. In a career. If you aren't already very wealthy, you're not likely to become so, unless you inherit or win the lottery. You can't make drastic career changes that late in life. You can't strategically marry if you're already married (and yes, before I get flamed, a lot of people do aquire wealth through marriage).
It is far harder to be a free spirit travelling the world if you've already got children and mortgage commitments. Your body and looks are only going in one direction, eventually, no matter how much you fight it with treatments and exercise. It will catch up with you at some point.
Just doing a lot of thinking at the moment and it seems it's just too late - I'd like to be super successful and wealthy and well travelled and to have made more of my looks whilst younger.. But the barrage of inspirational slogans saying it's never too late just don't ring true. Sometimes it is.