It is better to be content with what one has, if I had a job now then maybe I could live well but I am unemployed, still I am content maybe I will find a job in the future. Moreover, I am currently familiar with cryptocurrency and I have succeeded in earning money from it so I am content. Every person is always restless to get more but when they do so, that person consistently loses peace. However, it is better to accept your position and be content with what you have, accepting all the happiness, peace, sorrow.
Even though I agree with your point about humans being content with what they have, I would like to say that peace is less about what you have and more about how you use it. For example, if someone is rich, has a lot of money, has everything they could ever ask for, but they barely care about others who are in need, they never do charity work, and they mock those who are poor and needy. Such people will barely find peace in their wealth, and they will always be surrounded by problems and sorrows, and they won't even realize and acknowledge the reason for it.
Almost all religions say this, but even if someone doesn't believe in religion, they will still find peace in their life if they care about others instead of thinking about themselves at all times. If you are blessed with wealth, but you only keep asking for more without giving any of it away, your wealth won't bring you peace and harmony in your life, and you will always be worried and stressed.