I think IT's most rabid supporters, and here I think that Grant & Jerry are doing him a huge disservice too by constantly bleating about him like two starstruck teen girls at a Justin Bieber concert, are helping to exacerbate the impression that he is failing here.
When you get down to it let's assume that I am right. Its a safe assumption, I normally am.

But let's assume I am right, and IT is basically a 3rd option best suited as a score first 6th man. Ok, now if that is true, if I am right about that, IT's performances these last two games are not "failures". They are predictable for what happens to everybody's 3rd option/top 6th men when you remove the guys ahead of him in the pecking order. Would things go any differently for Jamal Crawford? For Craig Parsons? For our own Bobby Jackson back int he day (although not sure he was ever above 4th in the pecking order). I doubt it.
The impression that they are "failures" largely stems from the push, by IT, by his Beliebers, for him to be something more. Oh, he's a Top 10 PG, oh if you don't think IT is dreamy you just don't know basketball! (sincerely, Jerry Reynolds, President IT Flub Club). Oh he's an All Star caliber guy. Oh, he wants to be the best little man of all time. Oh...just etc. And yeah, if all that nonsense is true then sure, IT is failing to be that. There is a gap between that rhetoric and his performance. Its one of the major reasons why I have been bothered by IT getting puffed up like a blowfish as a gunning starter with a greenlight and legions of fans wearing little heart shaped lockets with his face on them. It ruins what should be a decent narrative. IT as 6th man, sans the overhype, the demands for shots as a route to respect, could be coming into these games as the plucky little 6th man doing his best to fill in when the team's stars were out, trying to carry us to unlikely victories while outmanned etc. Instead he gives the impression he's out there for himself, viewing everything a an opportunity to be the hero, to garner his "respect", as do the worst of his fans. And so yeah, now its failing. Its like the pretty homecoming queen form Middle of Nowhere, Iowa. If she's just a sweet humble girl with a pretty face and a nice figure, she's beloved and remembered fondly as a pretty girl that everyone wanted to dance with at prom. On the other hand if she and her escort claim that Mila Kunis and Nina Agdal ain't got nothing on this and she prances around the room trying to steal everybody's boyfriends, she'll be despised and ridiculed. And there is just no reason for it. Same face, same figure. In this case same basketball player. But by claiming too much and letting egos write checks that a 5'9" body can't check you can take what should be a success story and raise expectations to the point that it now looks like a failure, and its causing a backlash that is exceeding reality the other way. Now the girls are whispering in the hall about how heinous the would be queen is, how her nose is too big and she's probably got acne underneath her pancake makeup. And that's not reality either. Its an allergic reaction to the overreaching. She's still a pretty girl. She's just not Mila Kunis.