I’ve heard that before, and I think it’s clear that Lucas’s on financing tactics are to blame at least partly; he wanted to test out the CGI and also make money to fund TPM. What makes zero sense are all the later differences over time, particularly when some changes like Luke’s scream in ESB went back to the old version. The sad truth is that he’s probably just an obsessive old control freak, and this is his way of being involved in “his movies” after the other really creative minds have been forced out.