As far as I know path tracers (or super-sampling antialiasing) typically calculate the final color of a single pixel by averaging the result of all samples taken inside that pixel. This gives a nice anti-aliasing effect on the edges, however has the side effect of slightly blurring textures, because they most certainly do not have enough samples for each pixel, so samples have to be guessed with some kind of filter (like bilinear). From a mathematical point of view, averaging those samples applies a box low-pass filter to the reconstructed texture. This causes blurring.
How do path traced renderers/SSAA usually deal with this blur? Is there no way around it?