These new and well-financed firms would, presumably, be hungry to grow, operating under a completely different set of incentives.
The breakup gave the separate applications company, for instance, the freedom to port to any operating system, consequently giving rise to new Windows operating system threats.
How might the operating system company have responded?
The mobile revolution wasn't on the radar at the time of the antitrust case, but its disruptive potential was realized by Rebecca Henderson, an MIT economist, who told the court that cellphones "might one day attract developers in large numbers."
An independent operating system company, worried about desktop market share, may have realized the importance of Henderson's observation and moved aggressively.
Instead, Apple revolutionized the mobile market with the release of the first iPhone in 2007. And what did Microsoft release that same year? Vista -- a PC operating system that Microsoft CEO Steve Ballmer later acknowledged as something that "was not executed well."
Cloud computing didn't exist at the time of the trial, but the idea that server-based applications offered a desktop alternative was well known. And without a desktop operating system to protect, an independent Microsoft application business may have jumped into this area on pace with aggressive startups such as Salesforce.com.
In another major market, virtualization, VMware had a two-year jump on Microsoft in building out its technology.
Would a separate Windows operating system company have acted sooner?
For its part, Google used its search engine to quickly dominate the online advertising market and is now using its wealth to fight Microsoft on multiple fronts.
Microsoft's search engine, Bing, arrived in 2009.
During the antitrust case, Microsoft's attorneys argued repeatedly, but to no avail, that the tech industry was certain to produce potent threats. But the government's focus was on the immediate, and in the forefront was Netscape's browser.
The government charged that Microsoft was using predatory business practices to attack Netscape. In 2002, Microsoft had more than 90% of the browser market, but today it now has about 55% of the market.
It is impossible to know whether Microsoft's two successor companies, had a breakup been imposed, would have had success beyond what their parent has achieved.
Microsoft remains a very formidable company and strongly positioned in areas such as cloud computing. It is fully capable of taking a leadership position in hotly contested areas.
But as the last decade has shown, the same is true for other companies as well.
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