Just to give you perspective of how much money is out there.
Gold market - 7trillion USD
Global stock market - 70trillion USD
Global money supply (broad money) - 90trillion USD
Global real estate - 220trillion USD
Offshore tax haven accounts - 30trillion USD
Derivatives market - freaking huge!!!!!
There is enough money out there to push Bitcoin to crazy highs!
That's the last thing I'm worried about. It's just a question of time.
So BTC current marketcap is already 1.6% of that of gold's (few years back this would be considered a wet dream) and 0.16% of total broad money (if your numbers are correct). I'd say that's already a lot.
It's crazy to assume, that just because there's a lot of money in the world, all the money will flow into Bitcoin for no particular reason.
But it isn't for no particular reason though. Bitcoin is a superior kind of money, one that is resistant to censorship and is neutral on who participates. Given all the properties of Bitcoin, if you ELI5'ed (explain like 5yr old) it to somebody it would be hard for them to resist what lays in front of them. That is why I think reaching the market cap of gold will not only be easy, but inevitable.
And it is a lot already yes, but just because it is so, doesn't mean the growth will stop. Look at the number of hedge funds entering the space in the last year, I bet they have tons of $$ behind and they simply can't enter the market effectively yet. I don't think we seen the last of Bitcoin making a huge run, the only question I ponder is this sustainable long term? I hardly want Bitcoin to reach 100k+ then to come back down to 5k, I would like it to remain there and become worldwide accepted currency.