Umm, what possible reason do we have for thinking that the Borg would be stupid, either at the level of individual Drones, or at Collective level?
Sure, they look like zombies. But so did Isaac Newton. Sure, they move like cripples. But Stephen Hawking is worse. Even if they smelled phenomenally bad, they would only be matching Albert Einstein. None of this has any bearing on their ability to do research.
The average Borg doesn't engage in chit-chat. That doesn't make it a poor researcher; to the contrary, it reduces the laboratory hours wasted on coffee breaks or water cooler conversations. Witty remarks and clever ideas can fly back and forth along the inaudible Collective channels. With trillions of brains having Eureka moments, some
of this is going to rise above the research speed of your average, non-cyborg culture.
It's not as if we ever heard that the Collective would treat Eureka moments with "Shut Up And Keep Walking Slowly Towards Phaser Fire" put-downs. To the contrary, the Borg Einsteins are in the admirable position of being able to efficiently work on their theory of general relativity even when
walking slowly towards phaser fire. They just have to do the slowly walking bit in addition to being brilliant minds.
And if this Vinculum stuff is to be believed, the Borg "souls" are essentially immortal. Once the Drone body is gone, the innovative spirit of the assimilated Einstein still lives on and keeps interacting with the other minds in the Collective.