Wikipedia is nearing completion, this article says. That is, the project is out of its revolutionary phase, and entered long-term maintenance – adding new knowledge as it develops and updating existing pages to reflect new discoveries.
This may not be fully true. There is a lot of “ancient wisdom” to be re-discovered and added still. On the other hand, this task may be more similar to the other routine maintenance tasks, in that they require more specialised knowledge, gradually enhances the information provided by the encyclopaedia, and is part of an asymptotic approach to full completeness that can never be reached anyway.
One argument why the current state of Wikipedia may be a local optimum is that there are still many regions in the world where unfiltered internet access (or access at all) is not the norm. Or the focus of the people living in these regions is on basic needs, food and shelter, making it impossible to look after things that are higher up on Maslow’s hierarchy of needs. So once these regions connect and are free to use Wikipedia and contribute to it, we may see another jump in the volume of information kept in it. This explains the relevance of demands for a right of internet access and net neutrality for developing the global commons. And congratulations to Wikipedia – you are now part of the heritage that you were created to collect (aaah, recursion :-) ).