We have no predators but we do have a lot of existential threats. The more we spread out the more chances we have of surviving. If we sit on our hands and stay put we’ll wind up like the dinosaurs one way or another.
Solving world hunger does not need expansion. Stopping climate change does not need expansion. Preventing the upcoming antibiotics crisis does not need expansion. To the contrary, expansion makes all those things worse or has even started them in the first place.
This problem is twofold. First is that much food is produced far from many poorly nourished people. This problem is totally solvable by modern transport. There are enough charity donations to prevent hunger everywhere.
Second, and most importantly, it's the social structure what prevents ending the hunger where the hunger still is. People prevent production and distribution of food in order to keep the social structures where they are on top, or are fighting to be on top. They themselves are not hungry, and don't care about the rest much.
That's just what species are selected for. If you have two competing populations and one multiplies and expands just slightly better than the other, everything else equal, then that one will eventually outcompete the slower one.
But it does not have to be that way. Humans are the top predator, so no competition here. We could make do with limiting expansion if we chose to. It's still life, but without this "quality" that you seem to consider a necessity.