According to my understanding of the article, he
could be right if the Bitcoin (investor) community continues to use
BTC in the same way than today. Pure speculative use would eventually lead to a long term peak, and Bitcoin would have a hard time to revert a bear market of more than 5-7 years in this case. If the old growth pattern with the 4-year cycles is broken, profit taking of one of the next cycles could be followed by an extreme panic.
However, the community can revert this, in my opinion. At least, I'm not convinced about an "automatism" described in the following part:
Famas skepticism stems from bitcoins reliance on speculation rather than intrinsic value. He noted that with a fixed supply, its price is entirely demand-driven, making it inherently volatile.
(
Source)
He is here not referring to the supply on the market but to the complete circulating supply which is fixed. Current volatility however is largely unrelated to the
circulating supply but more reliant on
market supply and demand.
The game of market supply and demand depends entirely on
how investors behave, when they buy and when they sell. This means that if the dominant investment pattern changes, volatility could go down drastically (and it's already
decreasing quite steadily).
I believe that he's a bit correct that Bitcoin will be a bit more volatile than fiat forever. But if Bitcoin had the volatility of gold -- which has also a very limited "circulating supply" -- then it would be very useful to save money for almost everybody, and also useful as a medium of exchange.