I'd be more inclined to say that things are better now because of better sanitation, better availability of food, and better medicine, all of which have lead to increases in lifespan.
I don't have much to back me up here besides a hunch, and I'm not going to man the barricades defending this theory, so feel free to shoot it down. I'd say that humans have always handled roughly the same amounts of information, and it's just that the way of getting that information has changed. Once it was oral tradition and simple observation. Now it's digitally shared and stored.
Is there any fundamental difference between listening to gossip about the goings-on in the next cave over and seeing status updates about the friend of a friend's kid's new quad-runner? I'm skeptical.
You did hit one nail right on the head: sanitation. We take it for granted, but it was one of the biggest single advancements in human history. Humans used to be exposed to dramatically higher levels of ambient microbes. That's why seemingly trivial injuries (like a small cut) often led to sepsis and death. Nowadays, you get a small wound and you probably don't have to do much of anything to avoid infection except maybe keep it covered with a bandage for a few days. The risk of a life-threatening infection is quite low, and even if you do get an infection, as long as you seek quick treatment it won't kill you.
That said, not all of humanity has reaped the benefits of sanitation--witness the ongoing cholera epidemic in Jamaica.
On the subject of how much useful information there is: I think there's a lot more today than in the past, for the reasons others have laid out. There are simply more people, thus more communication and information. Our ability to share information instantly allows quicker synthesis of
additional information. And then there's the fact that we can store it so cheaply. But a lot of information is of very limited relevance beyond a specific use case. Witness
sojourner's car example. That kind of data is only useful either in aggregate (thinking engineering QA stats) or in specific emergency/maintenance situations (car accident, mechanic, etc.) Its general usefuless is rather low, and I think that signifies perhaps the biggest difference in the
types of information we store now. Most of it is very specific in terms of content and purpose, largely due to how highly specialized the labor forces in developed countries have become. The amount of
generally useful information has increased at a greater rate, but I don't think it's exploding nearly as fast as specialized information does. This isn't necessarily a good thing or a bad thing, just an observation. One way to look at it is that all the "easy" science has been done, and likewise the simplest tasks have either been totally automated or made into documented routines any literate person can follow. So our needs, as a civilization, revolve much more around that highly-specialized information than more general knowledge.