Encyclopedias exist to provide (a) access to information, (b) organisation, and (c) some guarantee of expertise. It's easy to take for granted how amazing it is to have a world of information at our fingertips, but the Internet itself provides greater access to more information than any encyclopedia ever could. (And of course Wikipedia deliberately eschews original content anyway.) We already have tools to organise and find information on the Internet: it's called Google. Or DuckDuckGo. Or etc. How much authority an encyclopedia has depends on how much you trust its editors to be, or be able to find, experts in the relevant subject matter. A search engine doesn't provide any guarantee of accuracy in its results, but then neither does Wikipedia — most people point out that it's up to you to follow the references and evaluate them. The things Wikipedia is good at are the things that the Internet itself is good at; and the things that the Internet on its own is bad at (e.g. vetting accuracy) is not something that can really be fixed short of turning into Britannica Online.
It's not quite that simple, of course. In theory, anyone can throw up a webpage on hemovanadin for the world to see, and it is relatively easy to do so, but it could be easier. What isn't so easy is collaborating — Wikipedia's greatest strength is also its Achilles' heel: anyone from anywhere in the world can contribute, constructively or destructively. But easier collaboration is a technical issue. There's no reason in principle that a centralised body should be required to manage all that. It's just that the availability and user-friendliness of the necessary software currently provide too much friction to ignore.