Failure in the context of a crypto-currency is when it fails to act as a trustless form of p2p money for those who use it + does not increase in adoption by users. Neither of those things are true.
Not who you're replying to (I'm a little higher in the thread) but I will take a stab at it.
The goalposts get moved a lot. Not by anyone in particular. The term "trustless" was not really in use until around the time of the ethereum launch. The goal of bitcoin was always only a digital cash system that has no central record keeper. It is currently a functioning, although inefficient, implementation of that concept.
To a broader point though, I say it often, you don't get to decide how the tools you build get used. Trying to do so is an exercise in frustration. Even if bitcoin were to never be used as intended, for it to be a success, it only needs to be used for something.
The main thing bitcoin (the network and codebase) did IMO is spur innovation into user generated currencies (and financial assets). Bitcoin itself is not that great, but some specific cryptocurrencies are wonderful. There are some emergent properties of these types of networks (they fork instead of evolve is pertinent to my point) that were not anticipated before they were live, and bitcoin can be viewed as a sort of prototype network that helped show us how to build and manage these things. For that, it is also a success, although I wouldn't dream of using bitcoin specifically to pay my bills, as it exists today. There are plenty of other currencies though that I would use to pay my bills, for various reasons.
