I have no interest in cryptocurrencies and I don’t own a single cent in any of them. But the continual barrage of hostile comments in every single HN article looks mostly like groupthink to me. Clearly cryptocurrency will continue to play a growing role in the future. Denying this seems simply delusional.
I think people have problem with assesing concepts that can only improve with time. For some reason people seem to think that all things behave like a runner "he can run fast now but he'll have to slow down and stop" kind of thinking. As if those concepts have possibility of reverting to become worse than what they are. You could hear similar voices around wikipedia, saying it'll never compete with professionally edi…
I think what a lot of cryptocurrency bears see is that blockchain-based currencies, especially BTC, have fundamental problems. Blockchains are fundamentally not scalable; since the more throughput a blockchain has, the harder it is to run a node, since every node processes every transaction. Another current problem is the massive energy usage of PoW blockchains. Concerning is that the biggest cryptocurrency by market cap seems to have no plans to research fixes to these problems, let alone implement them, and there is widespread opposition to change in general. Also, my personal experience is that 9 out 10 cryptocurrency projects lack clear technical explanations of how they work, with all the details. These problems coupled with the fact the industry is filled with hucksters, pumpers, and scammers makes people have a rather dim view of cryptocurrencies.
Perhaps these problems can be overcome (ETH is trying) but perhaps they can't, and if they can't then cryptocurrencies will be little more than what they are now (to a large extent), which is objects to fuel speculation.
And to be clear on my personal opinions, I wouldn't classify myself as a cryptocurrency naysayer, but enthusiasm is tempered and I believe that the current market caps are driven by speculation.