I could see open software being more important on the 100+ year scale (I could also see it not). The work or Bill Gates is very high impact, though.

Depends the value you put on potentially hundreds of millions of lives and what might be achieved by those people who otherwise wouldn't have survived.

Ultimately it's an apples and oranges comparison though and not especially useful.

That is fair. Open software could save many lives too (potentially more than the quoted hundreds of millions), but it is definitely a lot less clear or certain.

Also, wow! I knew malaria was a big deal, but I didn't realize it was that big.

It's massive. Also, the 100 year timescale helps...

Regardless of what you think about Microsoft, you have to say, Gates isn't messing around with some vanity project. The man has come to play.