Those had immediate, obvious value which were held back by the technology: every military in the world wanted flight (remember those Civil War hot air balloons?), as well as things like postal services, etc. There was zero question that as soon as the technology was functionally available, people would buy it. Similarly, the earliest photographs had unquestionable demand but were held back by the technology — again, zero question that people would buy it as soon as that matured.

Finally, the Internet was useful by 1982 — there's a reason why universities, governments, etc. all jumped online and agencies like NSF were funding this to support other research, not just development of TCP/IP, by then. The other big trend to keep in mind are the BBS scene and especially online services like CompuServe (which was already 13 years old by 1982) which had profitable businesses selling access to people who found it was useful to have in their lives for many reasons not related to developing or selling computer networking. Again, there was zero question of demand: computer hardware was expensive and networking was positively usurious but it was clear that growth would accelerate as soon as that changed because normal people found it useful for various parts of their lives.

Cryptocurrencies are different: since these systems rely on the now-pervasive web, most people on the planet have had access immediately. What hasn't happened yet is most of them having a reason to bother with it. Speculation has been the biggest driver but buy-and-hold is toxic to developing a useful currency and few people have built a business or life which depends on it except for gambling like that.