To be fair, that wasn’t a PT thing, that was an ROTJ thing. Look what Anakin’s spirit is wearing on Endor.
Back in '83 I assumed Anakin was appearing in Tatooine garb as a kind of symbolic ‘return to innocence’ type thing. In the original novels Anakin had been a farmer like Owen, so it made sense that he would appear in his old duds at the Ewok party. The idea that these robes were official Jedi threads is/was absurd.