Master Replicas originally wanted to have separable blades, then they decided against it because they got scared a kid would receive a flying detached blade up the head. At least I think that was the reason.
The very first ones had the socket, but the blade bolted in place. I've seen pictures.
I have made sabers, and don't quite care for removable blades. But it can mean changeable colors with the in-led style blades of Hasbro/MR. That could be cool.