I've read a lot of articles about people claiming bitcoin will be worth millions in the future, for example John mcAfee recently said bitcoin will be 500K in 3 years.
Now, imagine if this was true, and it was in fact 500K/BTC. The total market cap would then be 10.500.000.000.000, or about 10 trillion dollars. This is an unbelievable and unachievable amount of money. Even if we ignore the market caps, imagine how many people would become rich? Millions would become millionairs, hundreds would become billionaires, all in a matter of 3 years. This would cripple the global economy as we know it.
My best guess is that, in 10 years, bitcoin might be around it's absolute peak of 30K, giving it a total market cap of about 630.000.000.000$, or 630 billion. The total market cap of cryptos would then be around 2 trillion if the some of the better alts gain more traction. I believe this is fairly realistic. This means BTC would have to rise with around 7 - 8$ a day.
Edited
Well, I'm a hard bitcoin supporter and early adopter, but your argument looked very valid to me. You're problably right about that bitcoin can't go those excessive prices. Nobody should expect that. $500,000 or $100,000 are really not logical prices
The reason, the market cap is not unlimitedly open to grow. There must be an upper bound in crypto market.
That is a valid analysis and I agree with your points. However, I would not put a limit on the possible market cap, as counting the market caps as simply (Coins in circulation) * (Price) might lead to incorrect conclusions. Better to look at 24h trade volume, and in that aspect, bitcoin has been on the rise.
In general, $30k per BTC is a more conservative estimate.