The only tech you need to technically believe in is that blockchain could be used as a currency - which it already does act as, and then it is a matter of adoption.
Which blockchain? In the long run, most likely a blockchain would be used as a currency and it will have a quite large market cap, and the others will be near zero.
Indeed, which, and how does that winning blockchain algorithm allocate value. And will it be society as a whole that decides or the people who will gain the most value from their blockchain being adopted - with current algorithms making the earliest adopters have more value/other peoples' wealth transferred to them?