The total time of their tasks or the micro-benchmark of ripgrep?

Total time of what? Like what is the end goal that people are trying to achieve? All of the examples I can see in the post are similarly about development-internal stuff like tests and performance (or games). What I mean by true ambition would be stuff that is actually aimed at helping people in the world at large, not just helping developers develop.

Ambition doesn't scale with the number of small things you get done. Ambition is the size of the big thing you are trying to do. It's true that improving small things can help you do that big thing, but that's not the same as the ambition itself. Wanting to build a better mousetrap is just a modest technical ambition. The kind of ambition I'm talking about is wanting to eradicate the plague, and then maybe building a better mousetrap as a means to that end.