I was referring to Cryptocurrency in general. Bitcoin will be a store of wealth similar to gold... which is also much too "Heavy" and "Costly" to use as a day to day payment method... hence the term "store of wealth" is used. Payment layers will be handled by the much faster and cheaper blockchains such as Litecoin and Dash, and businesses themselves will create equity in their tokens. Its a whole new economy being built right under everyone's noses.. and I feel it will be an easily accepted replacement when the time comes.
And why should it be Bitcoin that is the "gold" and others the payment layers?
The question is not easy to answer in a really convincing manner. Dash supporters, for example, could say that their coin is "superior" or even "more valuable" than Bitcoin because of its enhanced privacy features. Ethereum supporters could give you the same argument because of their enhanced smart contract ability, and they already were dreaming of a "Flippening" this year (which hasn't happened, but they were closer than other coins before.).
But even if Bitcoin, until now, has never been "surpassed" by another altcoin, there is no reason for it to be, forever, "superior" to other cryptocurrencies. The only reason could be
usage as a currency, but that won't happen if it is too "heavy" or "expensive" for that. So speculation on its marginalization or even "death" will continue to drive volatility, and it won't be usable as an unit of account.
In my opinion, the "Bitcoin as gold" -> "other chains as payment layers" scenario could only happen with pegged sidechains. This is also the reason why I still have some hope for mass adoption, but the sidechain scenario still has to be investigated and must prove that it works. Otherwise, Bitcoin will just be a currency among many.