Here's the thing: due to the nonlinear value of money, if you're betting that something is going up massively then you're pretty much just as well off betting some of your money as you are betting all of it.
If I have ten million dollars, and I really think that tulip bulbs are going to go up by a factor of a thousand, it's still dumb to invest all my money in it hoping to get ten billion dollars. Instead, I invest half my money in it, because the difference between having five billion dollars and ten billion dollars is (in practical terms) small, whereas on the losing side the difference between having five million dollars and being completely broke is very large.
There's one exception to this: entrepreneurs frequently put all their money into their own company. Why? Because nobody else will, and because if the company doesn't get that money then the company will collapse. Wise? Maybe, maybe not, but it's wiser than sticking all your money in some random asset which, if not bought by you, would be bought by somebody else.
If I have ten million dollars, and I really think that tulip bulbs are going to go up by a factor of a thousand, it's still dumb to invest all my money in it hoping to get ten billion dollars. Instead, I invest half my money in it, because the difference between having five billion dollars and ten billion dollars is (in practical terms) small, whereas on the losing side the difference between having five million dollars and being completely broke is very large.
There's one exception to this: entrepreneurs frequently put all their money into their own company. Why? Because nobody else will, and because if the company doesn't get that money then the company will collapse. Wise? Maybe, maybe not, but it's wiser than sticking all your money in some random asset which, if not bought by you, would be bought by somebody else.