That’s surely puny for a manga, isn’t it?
It depends. From the point of serialized manga, 2000 pages is quite short. But Akira is not exactly a serialized manga. It tells one story (well, many, but all stories are interconnected in one arc). This is more similar to the “Graphic novel” or “BD album”.
Also, think that there is few filler in akira. Otomo’s style is very intricated, again, much more similar to european comics than japanese manga of the time. His drawings tend to be dense in details and with a very keen eye for the "cinematography"of the scene. This makes Akira a comic that sometimes is hard to read. There are few big vignettes, especially in the action scenes where usually the modern authors tend to embiggen and simplify.
So, from the point of view of Otomo, it was an epic task of extraordinary skill. To the point he never attempted again to write and draw a story so long: after Akira, he drew short stories for compilations (40-60 pages each) and wrote a couple of similar lenght ones (legend of mother sara ran for 7 volumes but was not drawn by Otomo). They’re saying that he wants to serialize a new long story, but I’ll believe when I see it.
