Even if all downloads were performed from the same site (which is not at all a valid assumption), the reasons may vary a LOT.
Just to give an (intentionally) extreme hypothetical example, say 10^9 users already have product A, while the other, product B is used by 10^7 users. If most users of product A are satisfied and don't have any problems, then they don't need to keep downloading it. Since product A has 100 times more users than product B, then you would see more downloads for product B. Is it better? More problems? Newer? Is its marketing? Is it...
The release cycle, built in updates, the specific download repository site and many more variables may be a factor.
The point is, there is no direct correlation to any particular reason and the variables are too many to make any observation / conclusion.