Maybe you meant something other than difficult, maybe you meant "easy" instead.
Having enough money to survive on for the rest of your life doesn't mean a life devoid of challenges, but to claim that such a life is difficult is probably a misunderstanding of what difficulty actually is for the vast majority of humans living on the planet.
For a lazy analysis also see: Maslow's hierarchy of needs.
For example:
I am now nice-dinner rich. I can buy good stuff from a local restaurant and not feel the sting.
But I am not business-class-RTW-ticket rich. I can, in theory, afford it, but I have to think about whether I think it's worth the money.
So, when you're deciding between food and rent, that is a different kind of difficulty than whether you have to decide between private and public school for your kids, and all together a different thing compared to whether you have to spend your time flying coach or business class.
As a sidebar, I think it's reprehensible that we (Americans) conflate having sufficient capital to guarantee one's basic needs with having sufficient access to capital to do interesting things (say create a startup) and also with having sufficient personal wealth to slake one's desires/whims.
I guess I notice this because I can still remember planning how to make a $20 note last until payday while not being hungry at bedtime. It mostly involved thinly-spread peanut butter on slices of bread.