the implication is that most people have a limit to how much money they can reasonably spend before they start seeking things other than more money in life.
even a poor person can tell you that an extra $10M in their pocket will be no more life-changing than an extra $1M.
I feel like there's a big difference between $10M and $1M. At $10M you're free to no longer work because of high returns from that money, you can effectively never worry about money again and live a comfortable life. At $1M that isn't true, you still need to work full time to maintain quality of life. $10M is obviously more life changing than $1M in terms of opportunities you can safely pursue.
if you were previously living on streets and frequently going hungry, then you can likely sustain yourself very well still without working. 1M translates to 27 years at $3k/month expenses. if you chose to supplement that with work, you can easily double that runway.
obviously it's not the same as $10M, which would allow you and your children to never work again, but jump between that and no food/no shelter is not as significant. for those who already have financial stability, $1M only serves as a safety net or retirement fund and cannot act as an early retirement plan without significant cutbacks, so the jump from 1->10 is significant. in the same way that 10M->100M extra income for Bezos is not gonna change much.
clearly you've never been poor.