It's good to see real data to address this question, rather than the neverending stream of basically anecdotal information about the problem that we've been slinging around. It's especially interesting to see the percent of not just "good faith" (flawed but well-intended) edits that are reverted but also the percent of "golden" (actually contributing) edits that are reverted; this sort of hostile drive-by is discouraging even for experienced editors.
One thing I see in the graphs is that the "survival rate" of editors who made a good-faith first edit was already in relatively steep decline by 2005, but the same rate for editors whose first edit was golden remained on a high plateau through 2006 and then just categorically dropped off a cliff. What happened then?
In 2006, bots were introduced to do various clean up tasks automatically. There are currently over 800 registered bots on Wikipedia. They are generally made to enforce the rules. But if you need 800 different bots controlled by 800 different people to enforce the rules, that means you have a lot of obscure rules.
For instance, there is a list of domain names that wikipedia sees often as spam. So if an innocent user goes to edit a page, and wants to add a new piece of information referencing a domain on that list, a bot will come along and mark it as spam (and revert it) even though its a good faith edit.
It can be frustrating and confusing for new users. The bot is often quite terse and rude, and so there is no incentive to return to wikipedia to make edits. 9/10 new edits are rejected, so no wonder they can't keep new editors.
I agree that it's nice to see hard data on this but
"the neverending stream of basically anecdotal information"
should be the first clue that this is basically what everybody seems to already know except for the foundation. This is not even remotely a new issue as their data and numerous complaints, articles, comments etc. shows, but it's taken them more than half a decade to even bother to notice it.
It's only in the last 2 years has the foundation even bothered to acknowledge there's a problem, and only after the problem became so bad that it couldn't be ignored.
One thing I see in the graphs is that the "survival rate" of editors who made a good-faith first edit was already in relatively steep decline by 2005, but the same rate for editors whose first edit was golden remained on a high plateau through 2006 and then just categorically dropped off a cliff. What happened then?