You're probably right. I hadn't stopped to think that authors might just use names that know work well for those characters.
On the other hand, using original names would make the characters be easily remembered and quickly associated with the name (for instance, when I think of the name
Romeo I can only think of
Romeo and
Juliet, but if I hear the name
Lucas I won't remember any character with that name).
Also, I think authors nowadays try to create original, non-stereotypical characters, so this lists of names suitable for each type of character don't apply any more (usually).