All economies are planned. The only difference is who is doing the planning.
But for real, a huge amount of very effective central planning is already done by private interests for the sake of profit. Big companies like Wal-Mart control huge amounts of the economy, and while they’re not in total control of everything, they are centrally-controlled within their sizeable boundaries. If planning didn’t work, Wal-Mart wouldn’t exist as we know it. The important question isn’t “does central planning work?” or “is it the most efficient/effective way?” it’s “who should be in control of the planning?”
If you want a really interesting view on central planning, look up Project Cybersyn. It was an experiment in a sort of hybrid centralized-decentralized planning of Chile’s economy using management cybernetics and early computer systems.
This reminds me of a book called The People's Republic of Wal-Mart. In particular this excerpt about when SEARS decided to run its internal operations as a competitive free market is pretty eye-opening
I think had an episode about SEARS: essentially they had departments competing with each other with advertising as the reward. Power tools ended up as the cover for the Mother’s Day newspaper insert.
Two folks have already suggested “People’s Republic of Wal-Mart”, which is defintiely what was on my mind when I wrote this post and is a much more fulsome analysis of this specific subject, but if this is interesting to you as an angle for viewing the world, I highly recommend the book “Thinking in Systems: A Primer” by Donella Meadows. It’s not an explicitly socialist text, but it’s a concise and very accessible introductory work on systems thinking, and it puts a lot of the key concepts in place to think about the world in these terms.