This is actually the reason I believe CRTs look better for a given resolution. The square reconstruction filter has a quite poor frequency response. If you look at a far enough distance (or good enough resolution), the cognitive low pass filter when you see the image is going to mitigate the problem, but up close it's quite bad. The smooth fall-off of CRT's pixel "point spread function" actually resembles a bit more the ideal sinc filter for reconstruction of bandlimtied signals. The square window has nasty zeros and decays very slowly in frequency.

I think manufacturers don't have a solution to this because the light producing elements inherently produce light across a small surface. They can't make this surface much smaller (and then apply a good blurring filter) since that would incur directly less brightness. Also, if they could, it would probably be more costly then simply making a larger number of smaller pixels (which also raises resolution).

I'm sure a lot of manufactures are not even mindful of these issues though, and I ssupect a compromise would be possible with some R&D.

EDIT: It's interesting this phenomenon is about the same across time. Some high-end monitor manufacturers are starting to offer strobed high frequency displays that don't exhibit the poor response of a window reconstruction. With a high enough refresh rate the temporal time constant of our visual system is enough to provide a good reconstruction. The difference can be seen in this video: https://www.youtube.com/watch?v=zjTgz9byxuo