Look at the price grapth for BTC / USD. A lot of ups and downs. The big green from December and January was abnormal and speculative. The price about 5000 USD equals the price from November. When you look at one-year graph you can see that Bitcoin represent stable growth beside this abnormal period.
Bitcoin price is one thing and its popularity is another: Think about it and look at the popularity metrics: UGLY!
The price isn't independent though, cause bitcoin's swing matter a ton for ALL the other cryptos out there