It's an analogy. It's supposed to help you visualize and understand what switching to a smaller unit of BTC would accomplish in the market. I'm saying that, LIKE a stock split, the quoted price would come way down (for a long time!) and the number of basic tradeable units would go way up. It is hoped this would increase interest in purchasing and/or trading small amounts of BTC thus providing more liquidity.
I'm saying that the community and the exchanges, and whoever speaks publicly for Bitcoin should switch to a smaller unit as the default unit voluntarily. Obviously Bitcoin is not a stock and no one entity owns it or controls its issuance. But by way of analogy we can see that adopting a smaller unit as the default reference for "a Bitcoin" in the public's mind is SIMILAR to when a stock has a great run up in price and the issuers decide to split it so that more people can get in at a lower price.
The hard limit of 21 million units is very small when compared to national currencies. This number is arbitrary, especially considering the fact that a digital currency will never run out of smallest units due to the fact that it is simply a number and does not reference a useful part of a tangible commodity.
This relatively low hard limit was probably chosen precisely to stimulate early demand for the benefit of early adopters, but that phase of the roll out may be coming to an end. If we want billions of people to own and trade Bitcoin, it is logical to promote a much smaller unit as the default unit of trade.