It requires a great deal of time and resources to develop blockchain software because everything has to be built up front. Doing an upgrade is not easy because nodes can choose not to upgrade and fork instead. Also, bugs mean people lose money and consequently faith in the project.
Tezos intends to solve the contentious fork problem by incorporating the governing structure into the protocol. Whether this works better than what is currently happening in the Bitcoin community remains to be seen.
Back to your initial question. Ethereum is a good example, but most of the ICO's that raised money recently won't launch until 2018-2019 at the earliest. In fact, some of them have innovation gaps. It's a long road.
How? I have yet to see anything useful built with it. Except for more ICOs whose use for now is moot, what problem does Ethereum successfully solve today that makes you say it delivered on its promises?
He asked about initial promises. They built the blockchain, virtual machine, programming language, and web3 API.
The ICOs haven't had a chance to deliver yet like I mentioned in another comment. Ethereum is the infrastructure and whatever is built upon it is up to everyone else.
"decentralized" wikipedia with a flat UI that requires 1.5Mb .js just for the landing page and running either a full eth node or a half-assed chrome extension (and hence isn't available on mobile).
As Jimmy Wales of Wikipedia says, "If everyone reading this donated $20, we would only have to fundraise for one day a year". Sounds like that would be a better way to spend money rather than on a vaporware pre-alpha token
Tezos intends to solve the contentious fork problem by incorporating the governing structure into the protocol. Whether this works better than what is currently happening in the Bitcoin community remains to be seen.
Back to your initial question. Ethereum is a good example, but most of the ICO's that raised money recently won't launch until 2018-2019 at the earliest. In fact, some of them have innovation gaps. It's a long road.