Right. WalMart and Amazon are closer to command economies than Gosplan ever was. They're not choking on the scale of what they do; they're thriving on it. Gosplan, the USSR's central planning system, ran on monthly reporting and annual plans. WalMart at one point ran on daily reporting and weekly plans. It's probably even faster now.

The problem of getting accurate data started to be solved when bar codes and RFID tags came in. It's possible for a factory to fake "we made 431 washing machines today." It's hard to fake "we made 431 washing machines today, their serial numbers were scanned as they left the factory, scanned again as they arrived at the various distribution centers, and scanned again when they were shipped to a customer, and scanned again when the customer received them." It's not airtight, but faking it requires a sizable fakery operation which tends to be detected eventually. Much real world activity is driven by all that "where's my stuff" data, and if the data is way off, people notice.

For large classes of products and services today, there is no real price competition. There just aren't enough players to make a market. The magic number seems to be four, from an EU study. Less than four major players in direct competition, and prices don't go down.