This is a very superficial analysis, if the price had remained static or close to it for so long then you may have a point, but that was not the case, the price went as low as 3k and as high as 69k during that time, the volatility was extreme and that volatility is what gives you the chance of making a lot of money as a trader by timing the market or as an investor by buying the dip or using the dollar cost averaging strategy during that period of time.