I don’t think those people you’re thinking about sail through life and never get bothered by anything at all. You probably only see them deal with things that are below their level of worry or frustration. They’re not going to be unbothered by the death of a loved one or major financial catastrophe.
However people who have good emotional control can appear to be emotionally invincible relative to people who are turn every minor annoyance into a catastrophe and are completely devastated by anything with minor significance.
> I've noticed it more in people who had a comfortable upringing and no money worries. Oh dear, dinner is burnt? No worries just order takeout! Lost your passport a few days before a holiday - no sweat, just pay the fast track processing fee. Car broken down? Just jump in a taxi. Coffee ruined your top? Just buy another one.
You’re only seeing one very narrow version of problems in their life that are easily solved by money.
I grew up around some kids who were very wealthy. Some had net worths in excess of $10 million in their 20s because their parents were tax optimizing their inheritance over decades.
While they were unbothered by simple things that could be solved with a credit card (burnt dinner, spilled coffee) they were, in general, much less prepared to handle the stresses of life than their peers. In fact, I can think of many examples where they fell apart and some who spiraled immediately into drug addiction the first time they encountered life problems that weren’t easily solved by money: Being broken up with by a love interest, denied promotions because they weren’t performing as well as their peers, doing poorly at their expensive colleges.
So I wouldn’t agree at all that wealthy people are inherently more resilient to stress. You’re only looking at a narrow set of financial problems which are already solved for them. Having those problems solved for them can actually lead to lower levels of stress resilience when the real problems come along.