Although I wasn't in the room when the executives of Microsoft decided to release, under strict control, I think it would be interesting to consider why the company would have made this move and why it made it now. The release was done in conjunction with the Computer History Museum.
Although some in the industry are hailing this move as making MS-DOS 1.1 and 2.0, as well as Word for Windows 1a, open source, this really isn't the case. Microsoft has released the code for these ancient products under a license, which allows access to the code "solely for non-commercial research, experimentation, and educational purposes." It forbids redistribution and restricts the use of the code so that it can't be used in another program. It even goes so far as to say that only 50 lines of code can be cited in other works. That's not all that open.
Open source licenses make it possible for individuals to copy the code, make modifications to the code, and distribute the results. Each of the many open source licenses control those three functions differently.
I believe that there are a number of reasons Microsoft has made this move, including:
Microsoft's client-oriented software model is under attack in the market. Smartphones, tablets, and other client devices are stealing Microsoft's thunder. It's doing its best to change how the company and its products are being seen in the hopes that this will sway consumers away from Smartphones and Tablets that are based upon Linux or UNIX operating systems.
The company is being forced to acknowledge that customers are using third-party devices and software. You can see this from Microsoft's recent release of a form of Microsoft Office for iPads.
From a messaging standpoint, it appears that this move has had some initial success. Much of the media believes that Microsoft has "open sourced" MS-DOS and Word for Windows even though that's not really the case. We'll have to wait for more time to pass to see if this move has really made a difference.
From a longer term standpoint, it's not likely to make much of a difference to academic institutions who are looking for ways to reduce their costs. Open source Linux and UNIX operating systems are more modern and are used in far more places than a 1980s operating system and personal productivity tool. More and more companies that could employ students coming from these institutions want Linux and UNIX expertise. All in all, this move is unlikely to make a difference in what these institutions are teaching.