If every spell caster and latent magic-user draws upon the Triforce for the power of magic, doesn the Triforce ever get tired or drained (to the point of causing wild surges or dead magic zones)?
I dont think that any mortal magic could even put a dent in the power of the Triforce. After all, it is the power or essence of the gods and gods have virtually unlimited power. Wizzrobes also draw from the world around them. The Triforce is the point where all the ‘ley-lines’ of magic converge. The Triforce is similar to a recharging unit. It continually puts out magic to be used by Wizzrobes.