Bitcoin can't even do anything; by the time it CAN do things, 2nd generation coins will have already eaten its lunch.
Anonymous transactions? No.
Instant transactions? No.
More than 10 tx/s on-chain? No.
Reasonable tx fees? No.
Reasonable tx times? No.
Functional governance system? No.
Is there any reason to buy Bitcoin other than to trade it for the cryptocurrency you actually want? No, and ETH and LTC are easy entry points as well.
It has none of the things needed to become a mainstream currency and is showing a startling lack of ability to implement such changes. Its development team has shown a shocking lack of foresight into the economics and required duties of a currency. Bitcoin is playing catch-up and trading solely on its brand name, not it's actual capabilities, and has been hemorrhaging market dominance because of it.
Market dominance decreasing nearly day by day... So if that is the main reason for bitcoin price it's not a good "reason"...
Maaaaaaybe. You never know. Bitcoin has brand recognition. It's literally insane how effective that is in our primeval primate society.
If that were the case there would not be new use cases exploding right now in Asia. Bitcoin has first mover advantage and whatever it can't do currently, it will be forked into doing at some point. It will be very difficult for Bitcoin to screw up it's first mover advantage at this point.