As I recall Lucas took interest in the retrofitting process quite early on but he just dragged his feet.
If he had jumped in and re-released the films in 3D right after Avatar it probably would have drummed up a bit more interest in the Blu-Ray sets.
After the Blu-Ray sets I can't see how adding the gimmick to a set of films people can watch at home in HD (even it's mangled form) will be worth the effort but I often under estimate the gullibility of Joe and Joanna Public.