Well.. I get what you are saying about K&N filters. have even read about those issues myself. K&N is very performance oriented filter so they skip on filtration performance quite a lot. Some filters are almost see through.
But.. ALL filter companies arent the same... BMC, AEM etc filters do alot better on filtration tests than K&N. Picture below.. And they use that cotton filter material aswell. Difference comes from simply adding more layers and some use felt like material in some layers.
S&B is similar. Said to be similar to AEM filters construction. Regarded to be more filtration performance orientated than K&N.
While K&N filters use 4-6 layers in their Highflow filters, S&B is said to use 8 layers.
https://www.motortrend.com/how-to/06...a&test=control
They aim for higher than 99% results in filtration efficiency tests, Often being 99.3 -99.5 %. There are some ISO5011 testing results as pdf-s out there if you google enough.
Also i get why you wouldnt want to use a K&N filter in offroad vehicles that probably face dusty rural conditions alot more than say a low sportscar that cant even go on many traillike roads without bottoming out. So its not that bad if you use your car on paved roads say 99.8% of the time.
Also according to the picture above we should all use old already gunked up filters as they provide the best filtration
Just joking.
Im sure we are just splitting hairs at this point.