By "valuable", I mean $$$ kind of value.
I completely agree that value doesn't necessarily translate into money, or may do so in such a diffuse way that it can't be turned into profit. Large, expensive projects that do good for society but can't be done "profitably" are why we should have nice, modern governments.
Define real valuable problems.
Curing Malaria is a real valuable problem. Sending your friends pictures (Instagram, Snapchat) is inane crap comparatively.
I'm not defending or attacking these by the way, I am just saying that "value" is totally subjective.
The majority of Startups aren't solving anything that the rest of the world would consider "real valuable problems" but that doesn't mean they wont use them.