What's hurting Diana's Sales

[Devaishwarya]

Yes she should be selling more...but...
As one of the iconic Trinity...her stories are just not written with the depth and gravitas that has always been given specifically to Batman and Superman. We do get moments of emotional and physical drama (for want of a better word) but those have been very rarely lasting or character-defining.
With Bruce and Clark, I get the sense that a lot of what happens in their books come about because of who they are and how they affect those around them...both good and bad. They're the catalysts. They're "cause" and "effect".
With Diana, she's...more often than not, just "effect"...which speaks to the "lack of focus" on her, solely and specifically.