Gold's market cap in US dollars is currently $7.1 trillion; Bitcoin's is under $0.2 trillion:
Current market capitalization in US dollars
Global money supply (broad) over $90.0 trillion [a]
US dollar money supply (M2) $13.8 trillion [b]
Euro money supply (M2) $13.2 trillion [c]
All coins and banknotes in circulation $7.6 trillion [d]
All gold ever mined $7.1 trillion [e]
Bitcoin under $0.2 trillion [f]
However, if you try to liquidate those assets, they fall in price. But some more than others.
E.g. there's no even $100 billion in Bitcoin invested. If someone tries to sell, say, $1 billion worth (1%) of Bitcoin, the price falls down rapidly and they never going to get anything close to the billion $.
Not so with gold. The price will fall down too, but not so much. One can easily sell 1% of the world gold reserves, for price close (lower, but close) to it's market value.
Maybe one day Bitcoin will behave like gold, but certainly not today.
I'm inclined to agree that bitcoin markets are far less robust than gold markets on the whole because of the long history and entrenched social position of gold. I do think you underestimate the effect on gold markets if they were flooded with someone trying to offload $70b of gold.
That's about 7 times more gold than the entire contents of the U.S. gold reserve of 8,134 metric tons of gold. I really don't understand why you think it would be easy to sell that much gold at the prevailing price.
Some random googling turned up about $100b/day of all gold changing hands worldwide, so you would have to sell it over a long period of time to avoid moving the price. If you were to try to keep your trades under say 0.5% of daily volume, or $500M, this would be the equivalent of trying to sell 1/14,000 of the total market cap each day, which would work out to about $12.5M/day if applied to bitcoin's market cap. Selling 0.5% of the daily volume of bitcoin would be more like $36.7M/day.
The reason for the difference in those numbers is that bitcoin turns over more of its market cap daily than gold, proportionally. So dollar for dollar, of course $1B affects bitcoin more than gold, but in terms of turning over 1% of the market cap the data suggests this might actually be easier in bitcoin.
E.g. there's no even $100 billion in Bitcoin invested. If someone tries to sell, say, $1 billion worth (1%) of Bitcoin, the price falls down rapidly and they never going to get anything close to the billion $.
Not so with gold. The price will fall down too, but not so much. One can easily sell 1% of the world gold reserves, for price close (lower, but close) to it's market value.
Maybe one day Bitcoin will behave like gold, but certainly not today.