I can agreee with accommodating old ~100ppi displays not being worth it past a certain point, but the way that Apple handles high DPI by standardizing on ~220ppi across the board is setting the bar way higher than most people can afford even today. The cheapest large format monitors which meet that standard are at least $1500, when you can get a 4K 160ppi monitor for as little as $200, and 160ppi is absolutely fine on systems like Windows which natively support fractional scaling. I think Wayland originally planned to work like macOS but they are in the process of implementing true fractional scaling akin to Windows.

Another factor is that focusing on pixel density above all else comes at the expense of pixel speed, there are no large monitors which meet Apples 220ppi standard and have a refresh rate of 120hz or better, no matter how much money you're willing to spend, they just don't exist.