Yeah never underestimate the vast armies of screeching kids in Target and their moms. Prequel-onlies exist. They are among us.
The James Bond blu rays trickled out separately (until MGMs problems) and I wonder why LFL doesn't do the same with Star Wars. They don't exactly have a vast, deeply varied catalog of beloved titles, you'd think they might want to spread it around a little. (And I think even the Indiana Jones trilogy is actually more like only 1.5 movies since he has to split everything with Spielberg.)