Perhaps this is because any good design requires some contrast. some sharpness to make it a good design. and modern carpets are all of a blend. Choosing a carpet with some contrast in it may help in this design flaw. but that means that. since it is done in a factory. the contrast will be repeated in the same manner over and over. That is what makes makes mass manufactured carpets so boring; the nature of the process requires that the same design is repeated every yard or foot or two. https://tommynevins.com/vinyl/grey/
This has to result in a constant repetition of the same little squiggles or curves. which can become annoying to the eye when repeated too much. Even if a repeated design is very well done. it is difficult to avoid the monotony and annoying features of a repetitous pattern over a large area such as a floor covering.