The graph above charts the retention rate for new editors over time, and the number of people we have actively editing. As you can see, it isn't positive. Wikipedia is in the middle of a crisis regarding editor numbers. We're driving away too many newcomers, and we're losing the lifeblood of any collaborative project: the contributors.
What this means is that we simply don't have the people to do the work we need to be doing. Backlogs go up and up, with fewer people to handle the mountain of tasks at Special:NewPages, or the maintenance of biographies of living persons (BLPs).
Featured and Good article promotions plateau as a result of not having enough people to not only write the articles, but review and maintain them. Everyone has a story of an area they work in where there just aren't enough people to get the job done.
The reasons why
We've got a problem, and there are many reasons why. Some people go away because they don't want to contribute productively, which is fine. Others go away because they find the community too hostile, or because they can't work out where to find help.
But ultimately, a lot of people leave because editing is just too complex. Back in 2001, when Wikipedia was founded, a lot of big sites expected users to write in markup of various forms, and we were one of them. Writing markup was a common skill in people who worked on the internet, whether that was BBCode, wikimarkup or even straight HTML.
The problem is that it's now 2017, and we are, if not the only major site still using markup, definitely the only one using markup of this complexity.
Moving away from markup
In 2017, people don't expect to have to learn markup to write something on a website. They're surprised when they come here and do, and most are not enthused by the experience. (We received some confirmation of that in a user test we conducted prior to the launch of VE.)
Many new users don't start off trying to make big changes; they start off trying to make small ones, and yet have to learn markup anyway just to be able to read the editing panel. They get intimidated, and they leave, as our user tests demonstrate.
This need for a better way to edit is something the community has recognized again and again, as early as 2004. We're building the VisualEditor in response; because people have asked for it, and more importantly because people need it.
Wikimarkup is already intimidating to newcomers, and the level of intimidation will only increase as other websites move forward. We're building it because if we don't, that graph is going to look a lot worse in five years.
We're not expecting everyone to use it (the source editor will still be around), and we're not expecting everyone to be convinced. But we're determined to do a good job and determined to demonstrate the impact this software can have.