It's obvious people intend to spend money when they have money, like a salary earner every month ending they just have the desire to buy much cause they have the money. They spend money on unnecessary things just to satisfy their desire. I think this are the common reasons why most people can't save their money, they lack financial discipline.
I personally, ever since the economy got so hard in my country I learnt how to manage my money, the urge to spend will always come but due to the economy I don't spend my money on things that are not necessary
In my opinion, the more income you have, the more you have to cover. I remember that I used to have a mediocre monthly income, but while traveling it was always sufficient and when there was additional income, unexpected costs always arose. So, the opinion that people are not optimal in saving cannot necessarily be said to be so, but perhaps there are several things that need to be addressed so that the desire to save is not delayed any longer. Yes. Everyone has a discourse there.
Mostly happens, as the more money you are gaining the more things that keep popping in your mind, if you are not a big fan of saving money chances that you will just buy all you want and not those that you only need, things that will be stored inside you that you have the money to spend and it's your chance now to please and reward yourself.
But, with those who know how to control and really care for their future, saving and investing is the best option they will keep aiming for more and will try to multiply whatever they've got.