A critique of most modern billionaires and millionaires is that they settle for ivory tower philanthropy throwing money around so they can chat with rich experts to figure out which other rich experts to give more money to. While good does come from this, it doesn't seem to make much progress in solving the underlying problems. For instance, how long has the Gates Foundation been involved with vaccines and pharmaceuticals and does it look like solutions are in within striking distance for the underlying issues?
As an example, a millionaire (who recently became a billionaire) decided on two areas where mankind needed dramatic improvement. Instead of ivory tower philanthropy, he started two different for-profit companies, one for each set of issues. Both companies have stuck around for more than 10 years and the issues they are tackling appear to have solutions within striking distance. A tangible difference has been made. If you didn't guess, the two companies are Tesla and SpaceX.
In contrast, it seems like the Gates Foundation is treading water with the issues it’s tackling. I could be wrong, but that is my perception.
As another example, an entrepreneur back in the day decided every desk needed a computer on it and used his for-profit company to make that goal a reality. That entrepreneur, of course, was Bill Gates himself.
Very few people have the R&D and engineering expertise, economic sense, and the money to lead a company to achieve world changing endeavors. Gates did it once. Musk has done it more than once.
Gates could start a pharmaceutical company, run it himself, learn the ins and outs, and reshape the industry along the way (if he could successfully learn the ins and outs). However, he does not appear to be willing to accept the risks involved in starting his own a pharmaceutical company and the problems of the pharmaceuticals industry remain unchanged.