Not true at all. The amount of liquidity on exchanges is mind-boggling small and the vast majority of Bitcoin isn't even in circulation. It wouldn't even take a quarter of that to pump up the price that far unless loads of hodlers give up and start dumping their old Bitcoin on exchanges.
Yeah. People tend to forget that it's just a fraction of all bitcoins mined which are actually "alive" and circulating. In reality, numbers we should be considering in practical sense of market cap are definitely a lot smaller.
Market cap is a meaningless number anyway when referring to currencies. Bitcoin is very unusual and it shouldn't be treated like the shares of a company - it's different and it's impossible to tell how much is in use or how much is lost or so many other factors. Some people just like their soundbites.