I don't believe artistic achievements - be they in the classical arts, theatre, music, literature, can be looked at so mathematically. I don't believe people would evolve in the way you suggest. Furthermore, it is human experience which dictates a lot of this type of achievement. You are a child once, then you are a child no more. You cannot see the world in the same way ever again. And if you have no children coming after you, you will lose that experience, and the contribution that arises from it.
The biggest argument to be had here, however, is whether or not you believe death is the end. For people who do not believe life ceases at death, there is little to no incentive to living forever. Whether you feel that you will be liberated after this death, or be reborn, or your soul reunited with your God, the fact is, death becomes just a step on your journey and not a final destination.
As a final point, I think humanity is too fucked up and most certainly too stupid to be allowed to live perpetually.