Ok thanks both for the responses.

So there is still room for growth in retail investors https://www.buybitcoinworldwide.com/how-many-bitcoin-users/ but there is still a max limit there

Modern websites say "In 2019, total world wealth grew by $9.1 trillion to $360.6 trillion"

https://www.visualcapitalist.com/the-88-trillion-world-economy-in-one-chart/

So if 1% of all that went into btc that would be $3.6 trillion which makes btc go about 4 fold

and retail vs institutional investors looks around even https://www.coindesk.com/bitcoin-retail-flows-jpmorgan

btc will never be a world currency because of the slow tx time, high cost, and low tx per second (all modern cryptos are better than it) so its only function now for big businesses like tesla (yes they sell cars for btc but waiting 1 hour and paying 20 usd on a 100k transaction is not a big problem) and investment banks etc is the hope it goes up in the future.

So eventually buyers have to run out and it may be a lot sooner than 2140 when the last coin is mined.