Laiste if people on higher incomes had any type of gratitude then they would never say that 100k was not enough.
Ditto those on anything over the average wage. You can have gratitude on even the lowest incomes as its not about how much you have but about your attitude and your appreciation of what you do have.
I could happily live on 25k a year and be grateful for it. I live on less and as I was lucky that I bought property years ago, I'm able to live on far less than is norm. Yes it's a struggle and I can't do as much or buy lots. I bought too much before at points in my life so living with less is actually calmer.
I'm grateful for what I do have and yes I'd like to change my car then I remind myself that's it's nicer than a lot of people have and that I'm lucky to afford food and bills. Even if I have to be savvy and budget to the penny to fit everything I want to do into my budget, I still have choices and I'm grateful for that.
It's about attitude. Someone earning other 60 or 70K that moans about how poor they are, is lacking gratitude, lacking critical thinking and they don't know how to budget or simply have too high an expectation of what they should be able to afford.
Comparison is the thief of joy. Some people on higher incomes have forgotten this or never knew it in the first place and so are not content.
Learning contentment should be a life skill.