no need to the pixel density of my phone is far superior to my wifes. however it makes zero difference. unless you hold it 3mm away from your eyes
Sure, if the scaling was linear in terms of visual perception but it isn't. There's a point of diminishing returns but even 8k isn't enough to reach it at 75-85''. A 6'' 16:9 phone at 1080p has 367 PPI, while even an 8K 55'' would only reach half that. At 75'' we're talking 117 PPI. Even a 27'' 4K monitor reaches 163 PPI only. If we look at 4K vs FHD again, we see that a 75'' 4K TV is no better in terms of PPI than a 40'' FHD one. Now, of course, how good that is will be up to the individual and I'm not trying to advocate that people should get one or the other, merely to try it out. Personally I couldn't stand my 40'' FHD for the one year I had it, and am certainly not looking to ever get that low in PPI again, so for bigger sized TVs there's only one solution.