Fundamentally making IE a free upgrade just when Netscape was claiming the browser market is no different, strategically, than failing to put anti-copy protection on MS-DOS in 1983 or encouraging easy copying of its "enterprise" virtualization software today. Similarly making it easy for users to "illegally" copy and install Office 4.0 for Windows 3.1X while straight facedly working with both WordPerfect Corporation and Lotus Development to help these companies prevent illegal copying, was a simple tactical extension of a long term strategy based on using piracy as a way of gaining market share.
Logically, in fact, you could see Microsoft's long term practice of advancing its desktop operating systems by offering MacOS features an average of about five years after Apple demonstrates their value as just that same strategy dressed up in a different outfit.
Look at Microsoft's current PR problem with respect to their Windows Genuine Advantage program and the anti-piracy features it claims will be in Vista in terms of the company's history, and you have to conclude that their willingness to impose these on their North American and Western European markets signals their believe that neither MacOS X nor Linux threaten their desktop dominance in those markets.
I think, unhappily, that they're right: Mactel is a disaster for Apple and Linux has lost most of its market momentum - in other words, I think Microsoft's customer base will tolerate almost any level of coercion either because they're co-opted into the program for commercial reasons, or have no workable alternatives within the remaining lifetime of the current NT (iVMS) code base.
In the long term, however, that code base is tied to x86, and now amounts to little more than history on the hoof as Microsoft transitions to the PowerPC architecture - and a new network oriented operating system. When that new OS arrives I think we can expect to see Microsoft trying for another ride on that same one trick pony: i.e. making it easy for users to "share" the first non games applications for their "System 360" (!) architecture.
A big part of the reason for this is that Microsoft's x86 future is tied to Windows - and Windows is as out of place on handhelds as an elephant in a Mercedes smart car - meaning that Microsoft's market share in handhelds is both trivial and weakly held because obtained at the point of its check book.
So how can Microsoft compete with Java in a billion phones this year?
Open sourcing their putative network OS will make it easy to publically deal with a BSD legacy, allow them to adopt the Red Hat business model for applications and support, eliminate the need for customer galling anti-piracy programs like WGA, encourage adoption of what would be an appropriate micro-kernel for handheld use, and speed the x86 to PPC transition.
All of which seems like such a strategic no brainer, that I'll predict right now that Microsoft does this -starting with an open source beta on the new OS just as soon as they can get a decision made, the legal planking in place, and the code out.