Your article is full of misinformation. Having been in the carpet industry for 35 years I can attest that Olefin (also known as Polypropylene) is the most susceptible to packing down, and thus performs best when it is used to make dense, looped carpet styles (like berbers).
Nylon and polyester are the best performers with polyester having an inherent stain resistance to most household stainants (dyes).
Solution dyed fibres have their color all through the fibre (like a carrot), while other dye methods place color mostly on the exterior of the fibre (like a radish). Olefin can only be solution dyed. Polyester and nylon can be solution dyed or other.