in my experience, a game which is of high enough quality AND sufficiently unique to be a "category leader" will require at least three months of intensive marketing and maximum exposure, before it begins to hit, if it will hit at all.
and i'm talking about a game that was thoroughly vetted for sale-ability. IE before the game was started, it was determined that (A) its colud be completed in a reasonable amount of time by the team, and (B) there's sufficient market, and (c) you can also beat any competing titles in the category when it comes to value to the consumer.
so somebody has to want to buy it, your game has to be the best choice (or only choice) available, and it has to be something your team can actually accomplish.
anything less, and you can expect less results.
and this approach: "others liking or even downloading the game is almost, but not entirely irrelevant"
will get just about the results you'd expect and are now seeing: none.
here's what i would do:
vet the game now. if its not worth marketing, stop and write something that is, or simply stop making games to sell and make them just for fun, if you can't or don't want to write something that has a good chance of selling.
if you design for success (sales), success (sales) is more likely.
if you do not design for success (sales), then success (sales) is much less likely, and largely due to random chance and dumb luck, which is not a reproduce-able business practice.