When signalling (or whatever the actual human decision-making algorithm is ) promotes activities that are correlated enough with good actual objectives, you'll wind up getting that stuff done anyways. If making cool products promotes your status and makes you millions of dollars as a startup, you'll wind up with high geek status and millions of dollars.

My point is that signalling isn't orthogonal to accomplishing things. They're actually pretty well correlated. Making millions of dollars is high-status. Fixing societal problems is high-status. Getting a project done is high-status. High-status things generally aren't that useless.