I think you said that backwards for what you meant to say, Michael, but I get what you mean.
No, ask your self why does a phone need a screen with a 2560 x 1440 resolution screen?
There is absolutely ZERO reason a 6" diagonal phone you look at from 12 to 18 inches away requires anything near that level of resolution to manipulate the pixels around. The only reason is marketing claims of "my screen has more pixels than yours has!" There is no way the human eye can discern the resolutions above number of pixels above the 326 PPI that Apple has provided.
Phil Plait, a physicist who handled the resolution calculations for the Hubble Space Telescope, explains why resolution matters and how the human eye cannot resolve more than a certain level in a 2010 article. LINK.
The human eye with 20/20 vision cannot see granular detail less than about 300 PPI at 12 inches (Actually 286 PPI). The average person is defined to have a resolution of 1 arc minute of resolution, which can only resolve a dot of 0.0035 inches at 12 inches. Apple's Retina display on the iPhone is 40 PPI greater than that limit at 326 PPI, which when calculated (1"/326) results in a dot of 0.0031 inches, below that limit.
I will grant you that a person with 20/10 vision, so called "perfect" vision, can actually resolve a dot that is 0.6 arc minutes, which is a dot of 0.0021 inch at 12 inches, which is a resolution of 477 PPI. Only 1% of the population has 20/10 vision. Most of those are under 4 years old and unlikely to be concerned with using smartphone screens.
A very rare portion of the population has 20/5 vision. . . above perfect vision, who can resolve a dot of around 0.3 arc minutes. Only those could possibly use the 515 PPI or the really ridiculous 577 of the Samsung Galaxy S6, which has a dot pitch of 0.0017 inch, half of what can be discerned by a human eye and requires the hard ware to push around FOUR TIMES THE PIXELS really necessary for clear images. Ridiculous, especially of they are moving images!
So Samsung is a bit like Spinal Tap. Our pixels per inch go to 577.