What I don't understand about these incredibly rich people is that surely there must come a time when they think to themsleves "actually I have enough money now." Personally I see money as a means to end so if I ever aquired enough that meant I could live the rest of my life pursuing topics of interest whilst living in relative comfort I would. But these people whos life is devoted to accumulating pennies just seems rather pointless.
What I'm saying is that beyond a certain point money stops being tangible and becomes abstract. If someone gave me £1,000 I could think of lots of things to do with it. Whereas if that amount were to be replaced with £1,000,000 then suddenly it becomes an unreal amount and I have no idea what to do with it. I guess people who naturally deal in such large amounts aren't handicapped by such things.
I used to think the same way, but over time my views have changed.
I remember when I first got out of college a $10/hour job was my goal. It took me 4 years to get, and I thought that I'd finally be able to get my financial house in order (this was in the mid 1990's, when $10 was worth a bit more than it is now). Yes, I was somewhat naive, but I also didn't have many expenses. I was single, had student loan and credit card debt, but that was it.
But over time, as I adjusted to this new normal, my expectations for 'just getting by' included more and more. A playstation. Internet. apartment in a nicer neighborhood. Fast forward through my career and I now can't imagine how I can go back to earning even 75% of what I'm making now - even though that's where I was just 7 years ago.
I can easily imagine that the people who want to make 100,000,000 more than they already have are subconsciously motivated in the same way I am.
In fact, I'd be surprised if there weren't some sort of evolutionarily advantageous algorithm kicking around in our behavior circuits that predispose us to consume & horde when we can, for the future is anything but certain.