tl;dr (uncharitable): "durr hurr ice can't possibly form in my freezer, that would decrease entropy since ice is more ordered than water"
Entropy only increases over the whole system. But the whole system includes the entire universe, not just earth. On our planet, energy is being plentifully provided by the sun (do they not teach this in physics any more?), and less plentifully but still in abundance by radioisotopes, mostly those deep within the core.
Which is to say, the future is fusion and fission energy, not oil. And we could in theory convert the earth to one big near-perfectly-ordered crystal of silicon and iron so long as we used up enough non-waste energy to increase entropy in the rest of the universe by more than it decreases here.
But also you can't just write S = k ln Ω on one line and "therefore capitalism" on the next. The arrangements of atoms aren't simple enough. You need to justify specifically why socialism will result in fewer possible arrangements, not just handwave past it all on the basis that the english language treats "order" as one big concept regardless of whether one means order-as-in-ice-crystals or order-as-in-social-order.