Good arithmetic here, but: There is a reason the welthy, and most other people for that part, have little money and lots of stuff. The reason is the inflation. What you call appreciating assets, is mostly inflation-safe assets. With sound money it is different, you don't have to panic buy these assets, therefore the demand for sound money might be higher than for fiat money, supporting a higher money value.
The point is that even if someday Bitcoin is worth more than all the currency in the world that is still a small fraction of all the wealth in the world. Your house isn't made of currency, Google isn't made of currency, the patent for a new drug ins't made of currency. They all contribute to the wealth of the world though.
I still believe that Bitcoin becoming the single world currency is a dubious and highly unlikely pipe dream but lets say it happens. Even those with massive Bitcoin holdings would still have a rounding error of the wealth of the world. Unless they plant to eat Bitcoins, watch scrolling screens of private keys as entertainment, and sleep inside a Bitcoin they are going to liquidate some of the wealth (which is already a rounding error on total global wealth) to buy food, entertainment, housing, etc.