FWIW, I don't think Eripiyo is oblivious, it's just that she puts Maina on such a pedestal that she barely considers herself worthy of breathing the same air :-P The fact that Maina could like her as a regular person has never even entered her mind.
I dunno, your last sentence sounds like it's describing someone who is oblivious to me.
I'd say most if not all otaku put the target of their enthusiasm on a pedestal, particularly idol otaku. Kumasa and Motoi don't exactly feel "worthy", either. Motoi obviously doesn't think highly of himself or his feelings for Sorane and Kumasa at some point says Reo would never give someone like him the time of day if it wasn't for the fan/idol context. They're nowhere near as resistant to the idea of their oshi appreciating their existence as Eri is shown to be, however. She's definitely a special breed of stubborn. That plus a tendency to talk over Maina (or about internal organs) contribute to their communication mishaps at least as much as Maina struggling to express herself.
Speaking of which, that struggle isn't entirely caused by shyness, either. The potential consequences of an idol overstepping the fan-idol relationship boundaries are significantly heavier than for a fan, so Maina is in a much trickier position. Connecting with Eri on a personal level would essentially require her to make a mistake - like slipping her contact information into that box of chocolates, taking advantage of those open twitter DMs, ...
Sorry for the wall, I could talk about this all day. Btw, just to be clear, "oblivious fool" was meant to be read in an affectionate tone, not a derogatory one.