The people putting photos into facebook don't have $4000 camera rigs. They have $500-1000 camera rigs, and the photos that they're taking are [often] taken using the pop-up flash, the kit lens, and automatic mode.
For them, putting photos into facebook is a completely reasonable thing to do, and their photos wouldn't gain anything by being stored on flickr.
IF you are a professional THEN flickr is the place for you. However, IF you are an amateur THEN Facebook is just fine.
We all agree that if you're taking a picture with a $4000 camera you lose something by throwing that up on Facebook.
Publishers regularly search Flickr for photos to license and use. I'm a point-and-click shooter, but out of the blue I received two messages asking to publish one of my photos (which I had tagged descriptively). I was paid, and I learned how to complete invoices and W-9s, and had the joy of seeing my photo published with credit in a food magazine no one reads (Whole Foods sold it briefly). Yahoo could better highlight Flickr's ability to connect publishers with casual photo-takers, by facilitating thorough tagging of photo contents and improving the search ability. Flickr's definitely a much larger and open body of content than Facebook for this purpose.
I consider myself a semi-serious hobbiest, my rig fits into the conditions above, and I still pay for my Pro account. I post a link to the album on Facebook, though.
If you're lucky. Mostly it's pictures off an iPhone or equivalent.
The camera in a smartphone is comparable to a $200 mid-range compact ( http://www.amazon.com/Nikon-COOLPIX-Digital-Camera-Optical/d... ) but not to $600 low-end DSLR ( http://www.amazon.com/Canon-Digital-18-55mm-75-300mm-Telepho... ) In fact the compact will have better zoom, flash, more megapixels... It will win on most metrics except ability to upload instantly.