Comment by adornKey

Having the focal point up close for a long time isn't that good for the eyes, so sitting closer than an arms length to a desk monitor isn't an idea that lasts well.

100 dpi with subpixel rendering already maxes out angular resolution (horizontal). It doesn't max out everything (retinal), so you still see some artifacts, but practically this is not that relevant. The price in energy/bandwidth rises quadratic for very little gain.

To get the equivalent of 4K at 100 ppi - with 200 ppi you have to put the burden of 8K onto the GPU... For now this is absolutely not good - High ppi is ok for small monitors and handheld devices, but for a decent desk with several good monitors GPUs just aren't ready yet.