Upload & Sell: Off
I was surprised how many people were using their cell phones to take pictures. They are probably using their same cell phones to take pictures of their children as they are growing up. Can you even upload them to your computer?
Well, I wonder what they were thinking in return? "Hey, we're just enjoying a day at the Zoo, might take a photo or two. What is that guy doing fumbling all those lenses, taking so many photos? What will he even do with them?". I'm far from siding, as I do agree with your point in part, but there are a number of ways to look at it. You've chosen to experience the Zoo through a couple of cameras, lenses... will you really remember or care at all about these photos in 10 years? Just speculating for the point of the argument, so nothing personal :-)
As for phones, well... as mentioned some produce more than acceptable quality these days if used in good light. My sister actually has a 10x8 from her Galaxy S2 (not exactly a new phone now) that I was surprised looked pretty well. This was for reproducing in paint, not to hang on the wall or anything. So if you take that into consideration, why would the average Joe lump a second camera around? They don't, waste of time, waste of money, waste of space.
As for photos of your family, well, this is should be important for anyone I believe. But isn't it just a reflection of the self image obsessed world we live in? Not to be dramatic, but I do think this is part of it. If you use Facebook at all, you will understand what I mean. The worse I've seen for family photos is someone using an instagram ish filter for their baby photos, awful green, scratches, high contrast, over sharpened, very dark - Great, your child looks like it's a a victim from a horror movie. For me I can naturally relate it to wedding photography - friends of friends experience cheap, shoot & burn, and realise what they're left with. Over time, some people will realise what they're left with. For the others, ignorance is bliss...
What gets me more than using the cell phone are the people that haul their iPad around to take pictures with it.
I was at a small exhibition last year and there was some guy walking around with his iPad level to his face, photographing every single piece (every time followed by a flash of light, as if it wasn't annoying enough). I'm not a confrontational personal, but it really p*ssed me off. I was just trying to enjoy & understand the exhibition like most normal people would... he didn't really say much, walked out of the exhibition straight away...