On the bolded part, I thought they don't resort or rely on their investments? Remember, you said earlier ' those ' , so meaning this includes other investments and not just Bitcoin. But if they also invest on others, then they will only give and take. Like for example they will use the profit of their other investment in BTC today and then next time they will now sell their Bitcoin as it have matured already and then some these profits are now going on to their other investments. After all, it is not only about having enough money but it is also about having a long patience and I think this is something that can't be matched by any amounts of money.
That is true, having the patience to be able to wait is the thing that drives an investment bigger. If anyone ever calculates how much their investment can grow in compound if they keep investing and not take out, then they will realize that after 10 years it may not be much, but in 15 years it's a lot and in 20 years it's huge. Why that much difference between year 1 to 10 versus year 11 to 20? Because you are not making the same return, you are compounding. Just think of this, if you take from 2 to 4, and then 4 to 8, and then 8 to 16, it took you 3 years to go from 2 to 16, it's 8 times bigger and you just turned 2 thousand to 16 thousand in 3 years.
However, if you take 16 to 32, and 32 to 64, and 64 to 128k, suddenly you went from 16 to 128 in three years too, same amount of time, but suddenly it's 100k+ more income. And to prolong it further, 128 becomes 256 and that becomes 512 and that becomes a million. So as you can see, the growth is exponential, so waiting is VERY important.