Take Thompson’s recent analysis of the United States v. Google case. According to Thompson, the Google case needs be und

There is truth to the idea that in many online markets over the past 20 years, the most popular platforms attract more suppliers, which attracts more consumers, and so on, acting as the platform or intermediary between the two “sides” of the market. (Some, like David Evans, call this a matchmaking model.) Providing a great user experience, attracting suppliers, and improving the product through feedback certainly describes an important way an online company can generate an advantage for itself.

Here is the danger: If you think competition is all about brands and buzz (in the 1890s) or Thompson’s aggregation theory (right now), you might end up overlooking all of the other strategies and factors that could also lead to a lasting advantage. Consider Amazon. Thompson says that “the internet has made distribution (of digital goods) free.” But, as implied, that hasn’t made the distribution of physical goods free. And that is why a company like Amazon can, and has, gained a major advantage by building up a large physical infrastructure (warehouses), not unlike a steel producer in the 20th century, and strongly relying on a loyalty program (Prime). So, it turns out Amazon’s competitive advantage isn’t all about the fact that “on the internet everything is just zero marginal bits.”

Viewed more carefully, aggregation theory is — at least in part — a model of what idealized competition might look like online, in some markets. Competition driven by quality reflects what antitrust and net neutrality advocates want competition to look like — that is, the better product wins, instead of whoever owns the pipes (or the channels). But that doesn’t mean it is what competition actually does look like, even on the internet. And this jump from the normative to the descriptive is the major pitfall of Thompson’s analysis.

The problem is that his aggregation theory isn’t aspirational. Instead, it is presented as a description of how the internet has “fundamentally changed the plane of competition” in a world where “on the internet everything is just zero marginal bits.” It also takes as its assumptions: “Zero distribution costs. Zero marginal costs. Zero transactions.” In that, in some ways, it is like the older economic models from the 1960s, except that they were at least billed as models, not depictions of reality.

How does all this relate to antitrust? Antitrust should be dealing with the reality of anticompetitive behavior in markets, not ideals of how companies work. And it is the difficult job of the law to determine which of these durable advantages just described are part of fair competition (for example, a better user experience) and which are not (for example, buying out dangerous rivals, or exclusionary deals that keep out competitors). Here, the key problem with Thompson’s analysis is that he comes close to assuming this problem away by implying both that his aggregation theory is the real key to understanding online markets and that the winners are there because of aggregation, and not these other advantages and strategies, and that the product is therefore the winner on the merits.

If that’s true, then aggregation theory is no longer a dominant theory of competition on the internet — “a completely new way to understand business in the Internet age” — but merely another source of competitive advantage in some contexts. The advantage may also, as Jonathan Knee, my co-teacher at the Columbia Business School points out, vary greatly as between platforms. And aggregation theory’s assumptions (or assertions) of “zero distribution costs, marginal costs, and transaction costs” damage the model in any real-world situation where none of those are true. An alternative model—like, say a straightforward platform or matchmaking model—doesn’t depend on such assumptions and therefore is probably more useful, though it may require more background reading to understand.

Perhaps it is boring to say that silly old things like scaling physical infrastructure or consumer-retention frictions still convey major competitive advantages. Unfortunately, it may also be true. And in their hearts, the leadership of the major tech firms know this — the “tell” is what they do to protect themselves when aggregation theory suggests they should be invulnerable.

Here’s my send-up of aggregation theory: Imagine this is the 1920s and we were speaking of the invention of brand advertising, and someone says, “whichever brand has the most people attracting it will create a buzz that further favors the winner. Hence, traditional metrics of competition are out the window.”

Whether this is core to his theory or not, Thompson also takes a highly anti-empirical approach to switching costs. He endorses the old 1990s idea that “competition is just one click away,” which may have been true in 1999, but that can’t be taken seriously now — if what he means is that the costs of leaving Google or Facebook are close to zero.The real question is whether there are, for the average person, costs to switching from Facebook or Google to use something else. The assertion that those costs are near zero is magical thinking. Indeed, one of Google’s most important strategies over this decade — its tell — has been to increase those switching costs in subtle ways.

Well, this overstates matters, because Thompson himself, faced with the actual Google case, to his credit, does not fall into his own novelty trap. Instead, in his post, he speculates that what might be at issue is duopoly collusion with Apple; he also suggests that other duopolies may be controlling distribution. (This insight, by itself, makes his post worth reading.)

When you look at all the big tech firms, in fact, they actually all rely on some mixture of tools for lasting comparative advantage. Facebook, obviously, relies on old-fashioned network effects, not unlike AT