Yeah Deadmau5 is pretty well known, but in comparison to most musicians Wikipedia page, it's not really that big. Usually with a musician, a huge portion of wikipedias articles are there long discographies, awards, nominations and etc. With Historical figures like that Rudolph Nazi guy, it's all just historical information, paragraph after paragraph.
It's not really how big the page is, it's the information inside it that counts.
Also DeadMau5 is brilliant, much better than Rudolph Hess in my opinion.