Competent minimap usage contributes to about 30-40% of whether you win a game or not.
Not to give the impression of undue combativeness, but I would go even further than that.
I've often though of "what wins a game" as being an intersection of 3 separate factors:
1. How well you maintain your map awareness
2. How "clutch" your play is, with the naut you are playing as.
3. How you spend your solar.
I'd say that anywhere from 50%-90% of a win is map awareness. In lower-league play, where it's more likely to be totally or partially absent in players on the enemy team as well as yours, it might be on the lower end. In higher-league and competitive, its going to be on the 90% level or even above. You simply cannot afford to not have it.
In contrast, I've found that I can afford to play "poorly" by other metrics and still have a halfway decent chance of winning a game. You can say a lot for just showing up and making an effort, even in a somewhat incompetent fashion. Here's the real difference between general (map) awareness and tactical (clutch) effectiveness - clutch play on the part of your allies can often partially or totally compensate for any lack thereof on your part. The same cannot be said for map awareness.
And I'm always amused by players in-game who criticize their allies on the basis of their upgrade choices. While they obviously make more of a difference the longer the game has been going, they are (imo) the least determining of the 3 factors in a win.
I think of it like a Venn Diagram of sorts - roughly 80% of what determines the outcome of a game is maintenance of map awareness. Roughly 80% of the remaining 20% is clutch skill. That leaves 4% for upgrade optimization. Counter-intuitively, what this also means is that at high-level play, clutch play and upgrade optimization are more
likely to be the determining factors in a win, because you can really only get there in the first place on the back of consistently decent general (map) awareness.