Great observation and good question!
As with any other coins, we take the decision to place market capitalization of a coin very seriously. Since CoinGecko.com ranks a coin based on market cap, we have to be responsible when placing market caps as it affects the ranking and visibility of a coin, thus making this metric predominantly vulnerable to manipulation by parties seeking to game our ranks.
At the very least, having a market cap assumes a coin is relatively easy to acquire and trade in multiple markets with significant liquidity... among other metrics.
At this point in time, Hive just hasn't met that liquidity requirement relative to the implied market cap due to how new this chain is.
That being said, this is very subject to change. We continually monitor the trading activity of Hive and other promising cryptocurrencies for when they've met the requirement for a market cap.
Very good points. Agree 100%.