Question:If the scenario plays out, does that mean that A) the price of Bitcoin plummets, but the miners are going to do something else? Or B) does that mean that nobody uses Bitcoin as currency but the price skyrockets because of the technological potential of the network being used for other things?
I don't see much logic behind his statements. He mentions not trusting Bitcoin because it is too young to have seen a full boom/bust business cycle. If that's how he feels, he'll have to wait another 10 or 20 years before jumping on any related technology.
If the price of Bitcoin plummets, then the real-world value of the block reward and transaction fees paid to miners also plummets, and some of them will find it is no longer economical to mine. As they drop out, profits to the remainder rise, so there will always be someone mining, but the network will be less secure. Mounting a 51% attack will become cheap. Because of this, the block-chain won't be usable to secure anything of value. So it becomes useless for coloured coins and the like.
Coloured coins won't create demand for bitcoins, because they generally only need a few satoshi to do their job. Hence they won't cause the price to skyrocket.
So he may mean (A), but that isn't really what he actually says. A lot of people see the flaws in Bitcoin, and conclude that it will fail and that some other altcoin will win, but I think they are mostly basing that on gut feel. It's a hard proposition to disprove, and it makes a good sound-bite, but that doesn't make it right.
At the moment it seems to me that the first mover advantage of Bitcoin, and the resulting network effects, make it almost impossible for another altcoin to beat. The only potential killer flaw in Bitcoin is the escalating costs of the proof of work mechanism, and therefore the only technology that has a chance of beating it is proof-of-stake, and I'm not yet convinced that PoS even works. Other features, like the choice of hashing algorithm, or the block time, or the transaction scripts not being Turing-complete - none of these seem like fatal flaws. Some economists argue that deflation is bad, and they may be right, but a kind of reverse Gresham's Law applies and Bitcoin will succeed even if the economy would be better off without it. So we're left with his vague unease about Bitcoin being 5 years old and not 25.