some get it, some don't?

I am complexed about how many "Mechanics" just don't get it... I work with two guys older than myself, I am no spring chicken but not old either.. One of the guys had a car with a p0171 as most know a very common code lean bank 1.

He had replaced the o2 sensors two weeks ago on a Saturday a day I don't work.. The customer came back with the same code IMAGINE THAT ! So they asked me to take a look at it with the other mechanic, I had shown this guy about fuel trims a few weeks ago. I hooked my scanner up looked at 02 data , maf , long and short term fuel trims.. at idle the LTFT was high 19 not high enough to set the code, and the O2 showing what you would think low voltage (lean). 

I raised the rpms and noticed the maf readings still low and the LTFT rising. At which point I put the car in drive and the LTFT really started to rise at idle and maf stayed low, I raised the rpms the car hesitated and the LTFT kept climbing.. 

I asked the guy what he thought he had no Idea.. So I told him pop the hood the air induction hose is broken between the maf and the throttle body.. He thought I was joking, He opened the hood and was in shock "how did you know that"? I told him simple I know what I am looking at and how things work, but my question to him was how come he did not know that. He looked like a deer in headlights.. 

He replaced the induction tube, at which point I hooked the scanner back up to show him that now we can prove our repair was good.. I asked him what he would think would happen he had no Idea. so I pulled up all the same items and told him to watch the LTFT and that it will fall quickly and the O2 would come to life.. Sure enough it did in fact the LTFT went a little negative -5 I asked him why he thought that happened he had no Idea, I explained it had been adding fuel for so long it is probably saturated and there is probably a lot of fuel still in the engine and exhaust manifold.. it would clean out as time goes by but that proves the repair is good. At which point I unplugged the scanner and that was that..

now today same lean code on a different car the guy looked at me I said remember what we did ? He said yea, I went over after about half an hour and he had not figured anything out.. in fact he had all kinds of not needed data up on the scanner.. I shook my head pulled up the fuel trims did a few easy checks noticed that the fuel trims went back in the good range with the rpms raised told him to look for a vac leak . HE found one I showed him the fuel trims again and how it verified the repair was good... 

He still has no Idea of what we went over! is it me or is there a need for a lot of learning to be done .. do some people just have the knack and others are just destined to be guessers and parts changers?