Yet, I don't think everybody can really agree on what is worthwhile for a person's time. I can point at people working on things like Linux and Khan Academy and say "Their efforts are worthwhile!" but then Microsoft and that one guy, who bitches about Khan Academy stealing all the VC money or whatever, will wag their fingers and say "They are hurting our business! Their time isn't worthwhile!"
Personally, the efforts DHH has put into basecamp and their products is worthless to me. I don't use the products and see no reason to start. That isn't a diss to the products themselves: I literally have no use for them right now. I freelance and study at college and their suite of products doesn't solve any of my problems.
So, who decides what's worthwhile? There are at least two instances where two groups of people don't all agree the same thing is worthwhile. It's a hard problem and implying "adopt my values so you will work on things I think are worthwhile" isn't going to solve it.
(Also, I agree we are in a bubble. I value economic growth and American strength, not pictures of cats.)