Because resources are finite, and already divided amongst older generations. It's a basic flaw in economy that the older folks don't want to talk about.
Depends whether you're considering the total useful resources of Earth (diminishing, e.g. fossil fuels), or total accessible resources (increased by technology). Or either of the above per-capita...
Except our resources are not so finite. At least in the first world, we have plenty of food for everyone. Grocery stores throw away millions of tons of food a year. We could use that food to feed people instead of letting it go bad, but instead children will go hungry "because a profit cannot be taken from an orange."
You're right though that there is a basic flaw in the economy that older folks don't want to talk about.
