I don't think high-DPI screens are as commonplace as it is continuously being repeated here. The only relatively common high-DPI screens are on the macbooks and higher end 13/14" laptops (250-300 ppi). If you move away from laptops and on desktop-sized screens (25-27") ppi quickly plummets. A common market monitor size/resolution combination is 27" at 4k resolution. This is roughly 160 ppi, although better than 1080p ~100 ppi screens is still nowhere near the pixel density of a macbook. So even on 4k screens the legibility of a heavily-serifed font such as Garamond is questioned. There is probably ONE desktop monitor with >250 ppi I can readily find* (Dell UP3218K) and that's almost $4k !! I'd say the author's argument still stands for anyone not on a ~$≥1.5k laptop. It's the same story as "we don't need subpixel antialiasing any more". Yes it's an ugly hack and yes you definitely don't need it on 300 ppi screen. Fonts are still going to look fuzzy on anything else.

[*] In the UK: https://uk.pcpartpicker.com/products/monitor/#r=768004320,57...