Gold is real and is money itself, therefore no cash liquidity is necessary. Neither bitcoin nor digital dollars on a ledger are real and are not money. Mighty big difference.
Gold isn't any more "real money" or any more "real" than bitcoin as long as there is the network infrastructure to support it.. gold and bitcoin both have pro's and cons. One of the cons of bitcoin is that it requires network infrastructure. One of the pro's is that I can send you bitcoin if you are in another state or country without having worry about physical delivery. Imagine trying to send a few bars of gold to somebody in another country, safely and securely. It would be expensive and risky. With bitcoin, it is extremely cheap and secure to transfer. You can do it all day, instantaneously, back and forth. Bitcoin also has much greater security than gold. Somebody with a lot of guns can come and take your gold, but there are easy ways to prevent this with bitcoin. Otherwise, they are similar as there are limited amounts of gold, and limited amounts of bitcoin.
If people stopped buying gold - let's say somebody found a way to produce gold cheaply using aluminum. People would run to the gold shops and start trying to sell at the current prices, but nobody would be willing to buy and the liquidity would drop the same way as if people ran for the exit on bitcoin.
Maybe I'm missing a piece of info but in order to cash out bitcoin into digital dollars, don't you still need to go back onto an exchange to do that? The exchange needs to have dollar liquidity to send to you, right? If they don't then how is it any different than the rest of the fractional reserve ponzi junk, where claims on an asset far exceed availability of the asset?
Like a stock, or like gold, the price is based on the last sale that occurred. That means at any price bitcoin is at, there are willing buyers and sellers. So when you cash out your bitcoin at an exchange, the willing buyers buy up the bitcoin and whatever the price they are willing to pay for it is, that is the current price of bitcoin.
I'm not trashing gold, gold is great. Bitcoin is great. They are both useful in ways that the other one isn't. People should own both.