Yup. Anyone can. Check this list out and the amount of fictitious value that has been created by tulip craze "investors". Hell, at least a tulip has a physical worth and purpose!Supply of Bitcoin may be limited, but anyone can create their own cryptocurrency, so the supply of cryptocurrencies is theoretically unlimited.
Kodak recently announced they are creating their own cryptocurrecy.
Check out the bottom of the list. There's about 500 of them that they can't even track a market cap because they can't even figure out how many coins there even are.
https://coinmarketcap.com/all/views/all/