I would like to hear an argument that the world is not better off. I'm not sure its possible to construct a coherent one.
I'd argue that the world is not better off because of science and technology. While this has nothing to do with our science and technology itself, it is important to see who controls these things. Most of the good things that come from science and technology are out of reach from a lot of people. Lets take advances in medicine. This is an area of science that has made a lot of great strides but which is not available to all people. Why? Most of it has to deal with money and the rest has to deal with location. If you don't have the money to afford certain medicine then how is that any good to you? If you live in a third world country and your village is in a remote area, how good is modern medicine? Resources and manpower are another issue. Yes, science and technology are good for me but that is because I have relatively easy access to it and can afford some of it. But I am not truly representative of the entire world. I guess the only problem lies within the wording of the question presented. I also think this is partly what thenewgreen hinted to in his comment a couple posts below this.
I think by your argument that it would still seem that on the balance we are collectively better off, unless you think that the negatives of not having access to medical care outweigh the positives of having it. That seems specious. We would be a better society if everyone could get good quality care, but then the goal should be trying to improve access, not scorning those who already have access. Also, even in remote regions, the poverty level and access to clean water have improved dramatically in the last several decades, even if hospitals are a long way off.