Galt's Gulch was much more Socialist Commune than libertarian.

Money had no use as Ragnar was running around distributing gold to everyone on a regular basis, John Galt had built a literal free energy machine and was giving the power away AND giving vanishingly cheap lectures on how to build one. Even the scarce resources (like the only car in the entire society) were being rented out for 50 cents a day.

Plus all these fiercely competitive supercapitalists would just step aside and just allow competitors to operate with no challenge. The iron mine, and coal mine were all running at industrial scales to serve a town of a few hundred (they had robot labour and free energy) and when the copper miner just showed up they just let him stake a an exclusive claim and start digging with no issue.

I highly recommend Adam Lee's critical readthrough on patheos.com https://www.patheos.com/blogs/daylightatheism/series/atlas-shrugged/