that can be fixed. in just a couple days.
make a altcoin with 50trillion coins. sell just 0.001 of a coin for $1.
making the altcoins market cap 50quadrillion dollars

all for the price of $1 sell

what you then learn is that market caps are a meaningless statistic to look at
what you learn is stock market cap is a meaningless number

stock prices are not based on some large pool of dollars held to match every share/stock.. its based on the current price of an order (of any % of a stock) and this price is then with no real dollar involvement multiplied by how many stock/shares there are

crypto market caps have no dollar reserve either. its just based on the current price of the last order(even if its decimal) and multiply that price by the coins in circulation.

so you can change the market cap of bitcoin by large amounts of $measure. without having to see any large amount of dollar spent