Those who use BioKleen as a specialty rarely clean really dirty carpet. Most of their customers don't drink Kool-Aid or Hawaiian
Punch. So it normally works well for them (it does for me). Many of my customers would rather have a spot on the carpet that wont come out then use something that might hurt their health (real or perceived). Disagree with them or not, the customer demands this service. I have customers who would freak if I used butyl or fragrances in their home. Many of the so called "green" cleaners (axiom comes to mind) would not be a good fit for them.
If you want to give BOK an effective shot you will have to boost it. Forget the traffic lane cleaner and just use the fiber glow liquid boosted with oxybleach and some citra-soy solvent. That makes a pretty effective prespray. Oxybleach is probably doing the heavy lifting. You may have to scrub traffic lanes. Rinse with scorching hot soft water only. Works well.
That said, it is totally inappropriate in most commercial settings or apartments. But you shouldn't blame a fly swatter for not working well as a hammer.
Of course you can ditch the plant based cleaners and go with Planet Guard. Still not strong enough for real nasties but works very well on residential (with out the foam) and many commercial jobs.
The worst chems-
planet guard degreaser - doesn't work at all
axiom deodorizer - doesnt work and stinks
encapuclean - total joke
skunk out (powerclean) - stinks so bad you don't care if its working.