I agree 4k is enough for TVs, but not for computer displays. 27"@4k still looks pretty bad on a desktop display. For desktop display, 220 ppi (27"@5k or 32"@6k)

I agree 4k is enough for TVs, but not for computer displays. 27"@4k still looks pretty bad on a desktop display. For desktop display, 220 ppi (27"@5k or 32"@6k) is perfect.