If the price of bitcoin shoots up to 5 figures, wouldn't people that had bitcoin earlier- people like satoshi nakamoto- be rich af? He has ~1mil bitcoins and if bitcoin goes up to 50k, then he would have $50,000,000,000...
What incentive is there for buyers to push bitcoin up that high? And how much would bread cost when that happens?

Money is not wealth. Real wealth is, for example, power but you can't buy it directly with money, though it can help greatly if used wisely. Bill Gates is said to be the richest man in the world (or whoever is claimed to hold the title right now) having 100B dollars of wealth, but this doesn't mean that he has that amount of money in his bank account. It is mostly in the form of property of property rights...
In other words, if you had an unlimited source of money, could you easily buy the whole world?