It’s a fact he’s given tens of billions to charity. What evidence do you have of him spending similar amounts on other things?

Except most of those tens of billions haven't gone anywhere and are still held by a foundation fully controlled by bill gates. The amount of it that drips down to actual charities is a small percentage of these tens of billions each year.

They are currently giving away about $5 billion a year.

I too would like to donate a few billions from my 100 billion pile of cash.

I mean why would he donate everything at once? That wouldn't really make sense.

Perhaps not all at once, but there are plenty of problems with underfunded solutions.

A few years back, I was fortunate to have a random conversation with a reknown researcher from Princeton Plasma Physics Laboratory. He was lucid and blunt: if we had more money we could solve fusion.

A couple days later there was news of China having done the longest running fusion reactor burst (?) to date. Two-plus minutes.

I keep thinking about that conversation and his "promise."