A truck mount wash will resoil faster then LM . Extraction chems can often leave a negative residue due to the rinses used. Encapsulation will leave a positive residue meaning it wont negatively effect the carpet. Lm is using encapsulation is absorbing soils from the top down. When you prespray your carpet before extraction which direction do the soils go? Your washing down and then trying to put it back up. With LM( if done properly) you didnt apply enough solution to the carpet to wash the soils to the bottom like you do with an injection sprayer. I have cleaned both ways for decades and have seen LM to stay cleaner much longer. When a larger amount hits the bottom and you cant pull it all out which is often the case you will/can create a wicking issue. Most guys also don't rinse the carpet more then 1 or 2 strokes so how dirty is the water left in the carpet? It can be the same as whats in the waste tank. Now before you want to cut my head off I offer both methods and make chems for both methods. I'm just witnessing to what I have seen over the last 10 years with encap.
This is also why you get far less wicking with LM. But to address your point its not the level of soil removed that causes a rapid re soiling but the type of residue left after the cleaning. If you use an alkaline rinse with your extraction you WILL be leaving behind surfactants that are sticky and this will resoil quickly. A clear water rinse is much better. The encapsulation polymer dries to a hard shell ( think M&M) and blocks off the surfactants from being sticky so it resoils at a normal rate.
The other issue can be that the cleaner in either case removed the soils stuck to the oily binder on the fibers thus making it look clean but did not remove the binders so it resoils quickly or the spot re appears.
I almost stopped reading after the first sentence, I thought I'd been transported back to the 70s, do we still peddle that nonsense about re soiling chemicals? It laughable that a silly point like that is needed to back up Encap cleaning.
I use a fresh water rinse, so I guess that argument does,nt count for me, or does a fresh water rinsed carpet also resoil quicker that Encap.
I don't believe any cleaning photo I see unless I did it myself its so easy to fake the 'clean effect' . the foam alone gives an immediate visual appearance of clean.
On those photos did he tell the customer that the dirt was still there just not visible so they will need to vac it up over the subsequent weeks? Encap is good in the right situation....... but that is not the right situation