Point One: Wikipedia is doomed to failure
A real encyclopedia is written, edited, published - and thus finished. You can write yearbooks to add information or new, updated editions every decade, but a published encyclopedia is done. Wikipedia, conversely, is never finished; it must always keep up with current events (for reasons beyond me), and it never tries to limit what it covers, so Pokemon character lists exist on the same site as the biography of Ludwig Wittgenstein. Certainly it's nice to have all this information together somewhere, but the end result is an unwieldy, incoherent mess. And then there's the issue of article fidelity; how many articles have hoaxed or malicious material? How many articles are hoaxes, like the fictional Soviet director Yuri Gadyukin?
A friend of mine, "Stierlitz", once called a plan to make a display encyclopedia set out of the English-language Wikipedia "[p]ure derp", but I think he had it wrong. To actually hold one of the 2,050 volumes in your hands, to see how lumpy many of the articles would look on the printed page, notice how the style can shift from paragraph to paragraph, that would dissuade people far more that Wikipedia is a worthwhile endeavor than anything I could actually write here, even without talking about MONGO.
So this is what Wikipedia really is, a giant tumor-filled shark swimming through a sea of information. A real shark would stop growing, but Wikipedia is an unnatural technological being which grows as it moves, and has no instructions to stop growing or shed unnecessary parts of itself. Such a thing is destined to die badly once it stops moving, and so it is with Wikipedia. `Bots have replaced content writers, editors are dropping, more and more articles have "hats" from years ago asking for the article to be re-formatted or merged with another article. If there had been a limit to the amount of information possible to display, or if each Wikipedia had been designed to be broken up between arbitrary categories (a History Wikipedia, a Science Wikipedia, a Pop-Culture Wikipedia), it wouldn't be the fiasco it is now. It would be a different fiasco, but possibly one more manageable.
Point Two: Banning people and deleting their work doesn't end "the problem"
Seriously, kicking people out DOES. NOT. WORK. Either they start up revenge blogs, or revenge messageboards, or they are just lazy and sockpuppet the site they were banned from. Take the example of "ScienceApologist" (now QTxVi4bEMRbrNqOorWBV); he started on Wikipedia in 2004, got into argument over argument over "fringe science" articles, blocked multiple times, was "permanently banned" in 2011. Spent from early 2011 to the summer of 2013 as a Wikipedia unperson, finally let back in under that bizarre handle. During his exile, became "iii" on the Wikipediocracy messageboard when it appeared in 2012. It should be said here that the man who runs the Wikipediocracy
It should be pointed out that the ban/delete culture slowly creates paranoia about sockpuppets, which beget a plethora of "rules" (which are repeatedly bent), which creates this inquisitor/commissar class, and before you know it the website begins to resemble the Imperium of Man in the Warhammer 40,000 gaming universe, aka what would happen if the Spanish Inquisition, an S&M parlor, and Frank Herbert's Dune were mashed together while everybody was out of the minds on LSD. This is why people quit (unless they like the abuse), and why this sort of thing is ultimately fatal for a free labor project like Wikipedia: nobody likes a creeping police state.