If I remember correctly,
DC Comics obtained the rights to all the
Charlton Comics characters. Alan Moore then proposed a mini-series which used all these characters; superheroes such as
Blue Beetle and
The Question.

After reviewing Moore's proposal, DC asked him to create
new characters for his story. So, Blue Beetle
became
Night Owl, The Question became
Rorschach, and so forth...
The reasoning behind it was to allow the Charlton characters to continue to be
used, instead of
destroyed. Let's take a quick look at how things turned out for Blue Beetle and The Question in the DC universe...

Hurm.