But they weren't wrong. Geocities and Pets.com died without making very much money.
The giants of the Internet were Search Engines, Online Shopping, Video Sharing, and Social Networks. The giants of "Blockchain" probably either in awful, primodial form (ie: Pets.com was online shopping, but a terrible experience. Geocities was also a social network... albeit a bad one by today's standards).
So today's coins probably will fail to some new coin made 3 or 4 years from now which really figures out the "killer app" of Blockchain.
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I think its fair to say that "Blockchain" as a technology will exist in the future. Back in the 90s, one could reasonably expect that "Jerry and David's Guide to the World Wide Web" was going to be the primary methodology of looking for new websites... before the Search Engine was perfected.
So many people lost their life savings chasing after fad technologies of the 90s, Webvan being one of the most notable. Billions of dollars invested and lost into just... awful ideas that no one understood.
Frankly, the neckbeards of the 80s were right. The vast majority of 90s webpages were utter crap without a business model.