You'll find that 10% of your time is spent producing really great results, that 10% of secondary sources you consult will be relevant and revelatory. The problem is that you can't just do the 10% of work that's really valuable: you have to do all 100% in order to get to that 10%. That 90% is not wasted time, but simply a measure of the inevitable inefficiency of things.
So proposals that people should do less scholarship in order to allow room for the good stuff to shine are misguided. If we reduced scholarship to 10% of what it is in quantitative terms, then the 90% rule (Sturgeon's Law) would still apply, but we'd have eliminated almost all of the good work along with the bad. By the same token, we wouldn't want to increase the volume any more than necessary either.
About 50% of work is going to be below average, no matter how much of it there is. Not everything is going to be excellent. Even in a research department like mine, there will be a wide range of metabolisms for doing scholarship. If everyone was like me, my department simply wouldn't function.