According to this, 800 ppm phosphorous is about the limiting factor to engine wear. I'm satisfied that GF-5 does not limit phosphorous beyond GF-4, at 800 ppm. Engines with roller valvetrains are much less succeptable to these lack of zinc/phosphorous concerns. And even at that, a modern factory DOHC solid lifter valvetrain hardly puts any additional stress on the valvetrain compared to a rollervalvetrain.
Toyota, the god of the automotive world, still primarily uses a solid lifter DOHC valvetrain.