Why does in almost all instances in the pali canon where Lord Buddha refers to himself he calls himself "Tathagatha" in 3rd person? Is it because Lord Buddha has eliminated self view? Or is it that when a bodhisattva reaches buddhahood he becomes the same as all previous Buddhas? Or a combination of both?
The Buddha sometimes referred to himself as "I" and this is not out of conceit or self view, but because he is simply using conventional language.
Why does he refer to himself in the third person as Tathagatha - "firmly established in reality"?
The way I see it, this is just like me talking about humans - "the human eats when he is hungry". Similarly, the Buddha describes his nature as one who is firmly established in reality, by speaking of the Tathagata in the third person.