220 ppi output with no subpixel rendering (ie modern Macs) has clearly visible jagged edges in angled lines and letters if you've got good vision or correct your vision to better than 20/20 (my case: I get headaches if I don't).

If you are coming from typesetting world, laser printers from the early 1990s did 600dpi (dots per inch), and that remains sufficient for smooth lines, though newer printers will do 1200dpi too. Going down to 300dpi printouts is crap.

Heck, newer Kindles do 300ppi and that can clearly be improved.

Apple's "retina", like all things in life, does work for 90% of the human population as advertised, but there's still a big number of people who have better angular resolution than what they target.

There's always "better" of course, but my point was more that "can't see the pixels" doesn't usually mean "I can't see the pixels if I sit back from the display a bit". When the iPhone 4 was introduced, no one said "what's the difference, I can just hold my (other phone) away from my face further and I don't see the pixels!"

Can you reference an example that shows this phenomenon with angled lines? I haven't had an eye test specifically, but my vision is generally fine, and I don't see the effect you're referring to, on for example a lower-case "y".

I have a 55" 8K and I can't see the pixels while sitting 2ft away. Everything is crisp and I have a huge workspace. For mac I use 4k native so 2x integer scaling.