Exactly, you will never see the types of gains that have already been seen. The law of large numbers takes over and it's just impossible to keep doubling in value at the same rate at this point. At this point, I wouldn't be surprised to see bitcoin's returns just mirror the stock market at large.
Many been hype for seeing the price way back before but this will never happen again although we have a chance when bitcoin price dump like when market season came but we cannot experience the same earnings where old dudes who hold became millionaire for holding bitcoin for so many years, maybe the least we can do for now is to ride with certain % gains and maybe you are right that maybe in future we will see the same profit we can get on stock in future when bitcoin price reach at 6 digits.
We're at about $50,000 right now. Bitcoin was perhaps the “best” investment opportunity when it was below $1,000, but it’s no longer likely to put up the super massive growth numbers anymore. At this price, it is just as likely that the a basket of technology stocks outperforms bitcoin from this point out. Bitcoin is likely going to largely correlate with the overall stock market from here.