Carnegie was an unusual rich guy. For example, he was a fan of progressive taxation. I did not know about his interest in Filipino independence. Thank you for that! Carnegie's philanthropy was driven by his personal passions. He not only loved libraries, he was a really big fan of pipe organs, paying for 7500 of them, mostly in churches. One can argue philanthropists should take a more rational and dispassionate approach, but the reality is that that fund things they like and understand.
The interests of billionaires don't always mesh well with the needs of the world but they can move quickly, and that can be important in developing solutions, especially in public health. I have really mixed feelings about the Gates Foundation's response to the Covid pandemic. All and all, I guess I am glad they made the investments they did, but the power they hold in the field of public health is concerning.
I think it is worthwhile to examine past examples of what in retrospect might be considered EA, to learn from both the successes and failures. Ralph Nader is a good example of advocacy work that can reduce harm. Beyond car safety, Public Citizen did a lot of work advocation for safety in the field of pharmaceuticals and medical devices.