Bitcoin has much more market share than Skycoin, yet that doesn't make it superior even if it was the first cryptocurrency to hit the market. It is true they took the world by storm and the value has done nothing but rise in the past few years.
However...
BTC is flawed
Although it has done great things for the world and has shown what cryptocurrencies are able to achieve from an investment and an operational point of view.
BTC is flawed in quite a few areas. Some of these are due to popularity, and some are due to basic design faults in BTC and Blockchain.
SKY, however, has taken its time during its development and fixes a host of these flaws while bringing some radical changes with it along the way. BTC is not the only crypto that suffers from these weaknesses as many of them have been developed to just take advantage of the cryptocurrency scene.
The same systems have been used, so the same flaws exist in these altcoins which do not bode well for them in the future.
The cryptocurrency market is over saturated, and any of the 1000's of altcoins that are available can vanish overnight as they have little to offer apart from false promises.