Retina is a very interesting example for how Apple works. They have identified the necessary resolution (200+ ppi) for this technology and worked towards across their whole product range. The technology isn't exclusive to Apple, but they are the only company which pushes it, even if it sometimes means quite odd display resolutions.
Other manufacturers seem to be completely oblivious to it. They still equip their laptops either with full hd or 4k screens. The resulting ppi are all over the place. Sometimes way to low (bad quality) or way to high (4k in an 13" laptop, halves the runtime). Same with standalone screens, there is a good selection around 100ppi, but for "high res" the manufacturers just offer 4k in whatever size, so once again the ppi are all over the place again.
Other manufacturers seem to be completely oblivious to it. They still equip their laptops either with full hd or 4k screens. The resulting ppi are all over the place. Sometimes way to low (bad quality) or way to high (4k in an 13" laptop, halves the runtime). Same with standalone screens, there is a good selection around 100ppi, but for "high res" the manufacturers just offer 4k in whatever size, so once again the ppi are all over the place again.