Batman's origin has been told many times. There have been some slight variations over the years but it comes down to the same story. Bruce and his parents go to a movie, they encounter a mugger afterwards, Thomas and Martha are killed and Bruce is left alone. It is then that young Bruce swears an oath by the spirits of his parents to avenge their deaths by spending the rest of his life warring on all criminals.
With Bruce's parents dead, he is raised by the family butler, Alfred Pennyworth. We are lead to believe that Bruce doesn't have any other relatives but that isn't the case. Looking back at Alfred's first appearance in Batman #16, he doesn't even begin working for Bruce until after Batman and Robin have already established themselves as the Dynamic Duo (Alfred was the son of the Wayne Family butler, Jarvis). Another question would be who raised Golden Age young Bruce (and don't say Aunt Harriet).
With retcons and the cleaning up of stories from the Golden Age (and even the Silver Age), we can accept Alfred did raise Bruce (in 1997's Batman - Secret Files & Origins, there is a scene with Alfred and young Bruce bribing a child protective services agent to make things work in their favor). But what about Bruce's other relatives? It has been shown that he had some before and even recently in The Return of Bruce Wayne. Why would his relatives allow him to be raised by the family butler?
Bruce Wayne's Grandparents
In Batman: The Return of Bruce Wayne #5 by Grant Morrison, Bruce ends up appearing in the time shortly after his parent's death. We see that (as part of Doctor Hurt's plan) Bruce talks to his grandparents, establishing that young Bruce did have living relatives living in Gotham. These were the parents of Bruce's mother. When (older) Bruce asked how come the kid didn't stay with his Gran'Ma, he was told that Martha Wayne's relationship with her mother had deteriorated years ago. Despite that, Martha's mother still cared for her daughter and believed Thomas Wayne had Martha killed and faked his own death (which we know was also part of Doctor Hurt's plan).
You would think that she would do all she could to ensure that her grandchild was protected rather than be allowed to be raised by the family butler. Perhaps it was a fear that the man she thought to be Thomas "Bad Tommy" Wayne would try to come after her. How come Bruce never asked Alfred about his grandparents? Even if Doctor Hurt did something to to them, it would make sense that Bruce would try to cling to any living relative he had left or at least attend any funeral services.
What about Uncle Philip?
Who was Uncle Philip? That's a good question. In 1986's Secret Origin #6, Bruce is saying his prayers and then swears to avenge his parents deaths. Are we to assume this Uncle Philip was just a family friend? Apparently neither Thomas nor Martha had any siblings. I just find it odd that after their deaths and Bruce was left all their money, no random relatives came out of the woodworks to try to gain custody of Bruce and get control over the Wayne fortune. Can anyone tell me who the heck Uncle Philip was?
What about other relatives on Martha's side?
I mentioned Martha's parents were still alive when she was killed. Their last name was Kane and I wonder about any relation to the other Kane family in Gotham. We have Kate Kane (who coincidentally) becomes Batwoman and her father Jake. Kate knows Bruce but it's never been mentioned that they were related. We do know that Kate is cousins with Bette Kane, aka Flamebird. It could just be that Kane is simply a common last name around Gotham.
I understand that Bruce growing up without parents and relatives is crucial in his journey to becoming Batman. I know Batman's story is decades old but with Grant Morrison establishing his grandparents were still alive, I just find it odd that no one would question a butler raising a child alone in a huge mansion.
The only thing that does make sense is young Bruce and Alfred threw around money to ensure that no one was able to take him away, including any other living relatives.