Market Cap is the oldest fud in the book which is why none of you naysayers above will make it.
"Most coins are locked up, I'd go so far as to say 95% of XRP are out of the market's reach, and therefore do not contribute to supply in the context of determining value. That leaves 5%, which is less than 5 billion XRP, and it's only THIS small pile of coins, that everyone needing to procure XRP, will be fighting over.
The "Demand" part of supply and demand, is an aggregate of many forces, but those forces all sum together at the point of purchase on an exchange. When demand is greater than supply, the price goes up; and vice versa. Demand for XRP will come from one thing, increasing usage. If I want to send my mother $150,000 worth of XRP, I will create demand. The more people buying their mother's shoe-shops, the more demand gets created.
You might say, well as soon as mom sells the XRP I sent her, we have a net zero situation and the price wouldn't change. Yes, you are correct, but if during my purchase, transmission, and mom's sale, someone else needs to buy some liquid XRP, there'll be less supply of them available, and the price will be higher. Extend this scenario to where hundreds of thousands of transactions are happening per hour, and you should see that a lot of liquid XRP has been converted to in-flight XRP, drying up the supply, and rapidly driving up the price because of scarcity.
In other words, the "volume" of XRP "utilization" trades (where XRP actually LEAVES one exchange for another for the purpose of value transfer, not speculative trading), will be what determines the basis for "real" demand, and it won't pay any attention whatsoever to said Market Cap. Demand is demand, and it will be satisfied at any cost. Higher volume, higher demand, higher price."