Bitcoin the word is an overloaded term. I think when people say Bitcoin, they really mean all cryptocurrencies taken together. You can watch all cryptos go up

Bitcoin the word is an overloaded term. I think when people say Bitcoin, they really mean all cryptocurrencies taken together. You can watch all cryptos go up and down relative to what bitcoin is doing. So, in that respect, there is no upper cap to "Bitcoin" since there are tons of coins and they all tend to balance out (of their relative worth).