Does it even matter? What is interesting and actually-important is that it is even possible. Just because most people do something dumb doesn't mean we should throw up our hands in defeat and build systems where it isn't even possible to do something smart.
It matters very much who the owner is of the currency you are saying can be transacted. If a large chunk of bitcoin adopters don't own the currency, can't transact, and can't withdraw into fiat, what do you have exactly? Just a theory that this could work if just everyone played by a very specific set of rules.
I honestly don't understand how you can possibly come to that conclusion, and in all honesty that people like you exist is part of why tech is so demoralizing these days. If a large chunk of Bitcoin adopters--or smart phone adopters or Internet users or ANYTHING--don't know how the technology they are using works and put themselves in a bad situation with it, it simply doesn't mean that the technology doesn't work... it just doesn't; and it certainly doesn't mean we should just give up and re-centralize everything. If you build something that can't be used wrong--or hell: that most people who aren't trained don't use wrong--you probably built something evil :/.
The fact that you don't understand means that you are looking at this through some very rosey glasses. The principle of blockchain and decentralization is fine, but we've come full circle where the easiest way to access and track the only marginally useful implementation of blockchain is through a centralized service. So far, the biggest headlines from blockchain and bitcoin have been fraud.
The biggest adoption came when people saw that money (fiat) could be made off of "investing". Bitcoin is a clown show. Blockchain, while probably useful, just doesn't seem to have any truly great applications yet.