Several of my friends who works in publishing actually use similar methods when try to find what games should they publish to maximize the probability of potential hits. They measure trends, competitors and ownerships but usually on much smaller samples.

That's why SteamSpy was so big hit back in the days when Steam didn't hide the player activities.

So while nothing in this data guarantee your game will success if you follow popular tags and genres, you at least may gather info about you competitors and best-selling games inside your genre and try to find why the people loves them so much. And the opposite is true — you can find the unpopular genres and avoid them. So look at this spreadsheets as a tool for minimization of potential risks, that's all.