In "Pioneers! O Pioneers!," a lot of what our speaker praises about these pioneers seems to be the way they face the hardships of charting new territory. Their sacrifice defines them. It sets them apart from the corpulent sleepers and feasters, and the drooping elders of the old world—the too-comfy folks. The safety and the comfort these pioneers give up makes room for them to take on the ruggedness of a newer, fresher world.
This poem tells us that material comforts make you weak, and our speaker suggests these comforts must be sacrificed in order to be a true American.
The way that this poem emphasizes unity and a collective pioneer spirit makes the hardship of individual sacrifice not seem as bad.