Have you ever put that much thought and time into a comment?
Surprisingly, I have. Ask @jedau. I've had many deep comments with him that he'll argue impacted him in very important ways. It wasn't about rewards, it was about a relationship and an important conversation.
That said, I agree with your general assessment, but I'm wondering, do I even need to upvote my own posts? I still get by okay without it and now I have more voting power for comments and posts from others.