Only the other day we were discussing the possibility of creating a history of game genres by parsing data.
Looking at it, the truth is that the platform part is more useful since the data it concerns is less prone to changing interpretations: a SNES is still a SNES after all these years. But the genre chart really shows how genre labels change over time: “arcade” is no longer a useful category, “action” and “scrolling” even less so.
As a supplementary chart, NcikVGG has posted a platform release history with an absolute vertical axis (counting # of releases). This one shows just how many games are being released these days compared to earlier days. It also shows us how important mobile platforms have become (though Android seems to be missing).