How are some academics able to publish so many papers per year (e.g., 50+ papers per year)?
If you look at big names in science, you'll see their name at the end of a ton of papers (in many disciplines like chemistry and biology, standards can be different elsewhere) and this is why: providing the money and the lab space gives "senior authorship". Usually they review the drafts coming out of their labs/collaborations, along with guiding students/postdocs at the idea stages (which is considered worthy of authorship by NIH/NSF and journal standards). People with big labs get to put their name on the end of every paper generated from not only their lab, but from their lab's collaborations and whatever their grants funded. 

Of course, some people are just crazy productive, but it's more likely that someone with tons of papers is getting a lot of them through their large labs.