Engineering teams often have reasons not to work on documentation - the backlog is too large, there are higher priority tasks, writing documentation is tedious, or there is no clear path to who the documentation is written for to begin with, so naturally all writing and content reviews are delegated to someone else. As a corollary to the above, I strongly believe that good docs for technical products require the engineering team to be a core contributor to those because the engineering team has unmatched expertise in the ins and outs of the tool, library, or the API being built.