The difference is Tim's solo was heavily premised on Bernard and not to mention the attempts to push Bernard via including him. Seems like a good indicator that he flopped.
They aren't iconic but they still are beloved by many and bringing it back twice despite death and universal erasure which they did for other couples is a testament it has staying power.
Batgirl 2009 was good and does support your view but Stephanie became popular and beloved during her time with Tim and was a well rounded character then.
Right now Stephanie doesn't have anything and is either used as the other Batgirl compared to Cass and Babs or a closet for Tim to avoid/prop for his new status quo. Breaking her and Tim up didn't magically fix the issues which plagued her.