After learning the truth, how did Dev rationalize his failure to recognize Sai Baba in the form of the Sanyasi?

Upon learning the truth from Jog, Dev felt immense shame and dejection for blaming Sai. As explained in Chapter 40, he reflected on why his perception had been so clouded. His rationalization was that the Sanyasi had first appeared before the formal invitation for the Udyapan was even sent to Baba in Shirdi. Furthermore, the Sanyasi's initial purpose was to collect funds for cow protection, a worldly affair. Because of this sequence and context, it never occurred to Dev that this same person, later asking for a meal, could be Baba himself. He lamented that if the Sanyasi had appeared for the first time after the invitation, he might not have been so confused. He admitted this 'delusion' caused him to overlook Baba's hint that 'two others will come with me.'