You might imagine adding up all the universe's resources: labor, land, raw materials, equipment, technology, knowledge, etc... into a pie. At different times, different people may have control of different percentages of this pie, but the size of the pie isn't constant. Improvements in technology can get you access to other planets, more solar radiation, deeper into the ocean or earth's crust, more efficient use of existing resources - thus increasing the size of the pie. If the size of the pie can be increased, then of course other actions can also decrease it.
This isn't to say nothing should ever be done about the relative amounts of the pie that different people control. Obviously the more parts of the pie allocated to serving a smaller percentage of the population, the less that will be available for everybody else. However, it is both a fallacy to say that society can only be improved by improving the pie's distribution, and a fallacy to say that society should only be improved by increasing the size of the pie.
Resource allocation is very important to the survival of society. If I spend all my time, food, and energy building a bridge that many people will use, while someone else spends all his time and energy building a bomber and explosives to take out the bridge, then in the end, the resources allocated toward both our activities were pretty much wasted.
On a less extreme scale, if I use up a lot of resources to build a bridge that nobody wants to use, then my personal efforts were wasted.
The spectrum continues: if I spend a lot of resources in trying to convince others to buy a product they didn't originally want (advertising), and keep doing it until I finally convince them to want it, and then spend more resources to produce the things they've been convinced to want, that too isn't exactly an efficient use of resources.