1. Microsoft has attempted to restructure its complicated licensing and has succeeded somewhat at the enterprise level. But the sheer volume of various products and different licensing methodology continues to confuse many. One example of how confusing it can be - there are seven different licensing structures for volume licensing.
   
2. While Microsoft has historically made it easy for the enterprise to incorporate new technologies into its IT infrastructure (e.g. updating Windows licensing for desktop virtualization), Microsoft obviously does not see licensing as a major issue to be resolved. If Microsoft - or any other software vendor for that matter - initiated reform of its licensing policies, it would create a number of issues, including a complete overhaul of all existing systems, a significant loss of revenue for Microsoft, and a redefinition of how software works within IT/business practices.
   
3. There is no centralized licensing practice area at Microsoft. Each product group creates their own licensing and pricing structure, independent of other groups within Microsoft. And, like any business, each group looks to its own profit center and headcount. With that said, licensing schemes can widely differ from product to product, even if the products are related. 
   
4. The Business Software Alliance and other third-party enforcement agencies police Microsoft's licensing policies for them. Since Microsoft does not have a centralized licensing practice, many of its licensing audits and enforcements originate outside the company. Once third-party auditors are introduced, you can bet that standard auditing of licenses and decision making on non-standard issues do not exist. 
   
5. With each new technology (e.g. cloud computing, multicore processors), Microsoft has to adjust its licensing structure, and that inevitably leads to adjusted or new rules and licensing scenarios. Unless you follow these small changes on a daily basis, the likelihood is that you're already out of compliance. 
   

In light of the unpopular Vista launch a few years ago, Microsoft needs the debut of Windows 7 to be a big success that will reverse their trend of declining revenue. This is especially true today, with a few strong alternatives to Microsoft's OS and desktop tools.

Whether Windows 7 succeeds or not, our point is still very valid - licensing is complex.
 
Some additional reading that might be of interest: 

Two new Windows 7 pricing details revealed....
Microsoft License Advisor
Microsoft windows server client access licenses