Seems like you've got a pretty hard perspective on how MMA knowledge is gained and applied - I try to be unbiased and just look at the fighters performance and the tactics/strategy they use to try and ascertain if anything was learned.
I wouldn't call it "a stretch" to say that Dustin learned something from getting grapple-raped by Khabib; in the 4th round when he took Dan down against the cage he went for a leg-lace to mount to single-leg back-take to Dagestani hand-cuff - this is TEXTBOOK Khabib grappling breakdown process and Dustin did an ok imitation of it (leg-lace his legs weren't crossed and he wasn't driving with his head into opponent). He's not Khabib so it's not going to be as effective, but that doesn't mean it won't still work.
Good fighters copycat the skills of other fighters, even if those fighters are better at applying those skills. It doesn't mean you have to be Khabib to use Khabib tactics, you just have to have better offensive wrestling then your opponent (and technically Dustin is better then Hooker there, he is just also bad defensively because he can't help but jump guillotines).
Good fighters improve from losses, especially if they got exposed somewhere (as it gives them an area to work on). That doesn't mean getting raped by Khabib turns you into Khabib, but in the process of the ass-beating if you have any type of awareness you have to look back and understand how effective it was and see if you can use those attacks/positions in similar ways if you are able to get there. You don't learn the technique through the ass-beating, you learn of the technique and then in training thereafter work on defending and using it.
If you don't think Dustin has been training positions Khabib put him in since their fight you don't know a damn thing about fighting.