Issues to be solved practicality:
The first blockchain (bitcoin) has initially been focusing on solving the "double spend" issue of digital currencies, when no central counterpart is involved. Later on, the blockchain was also used to store permanently proof of documents (hashes).
Blockchain infrastructures (Ethereum, Lisk, NEO, EOS....) added programmability features to existing blockchain , improved transactions duration and costs, but did not yet built an application-creator friendly environment.
Despite a web of numerous interconnected issues described in the following schema, a lot of crypto-entrepreneurs created some decentralized applications. user adoption did not follow (section 4.1 - dapp markets).
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