As RIM continues to grow, most well capitalized companies lose their chance to acquire it. You begin to only have Cisco, Microsoft, IBM and maybe Motorola or Nokia with the financial ability to do so. Ostensibly, Microsoft buying RIM makes sense. One reason: RIM is growing; Microsoft is not. With RIM's licensing model they aim to be the Microsoft of the wireless messaging world and have made remarkable inroads over the years. RIM creates the dominant platform in wireless messaging and a stable technology stack that other vendors can build and sell hardware and software. (Sound like somebody you know?).
RIM's email technology is built for the server and should be part of an operating system. Why would you want to handle messaging with the dependencies on the medium in which those messages travel? That's what RIM does when they install the server software in enterprises and in telecom carrier data centers. By integrating RIM messaging software in the OS, the solution becomes more economical and easier for IT to manage.
Developers writing software for the PC market are riding an anemic market in terms of growth. Not so with messaging and unwired devices. There is more innovative development of wireless applications as the number of installed devices reaches prodigious proportions. The only challenge I've heard from developers is writing code for RIM is burdensome compared with writing on Microsoft platforms. Assuming Microsoft keeps the RIM operating system around (another blog topic indeed), they would need to include a robust RIM SDK and developer plug-in to their much-acclaimed Visual Studio.
The naysayers claim that Microsoft would have never let a real acquisition target get to $40B before taking it out. Also the incompatibilities between the two operating systems make it like mixing oil and water.
With $61B in cash, Bill and Steve have a fat wallet but that doesn't mean the money is burning a hole in their pocket. Could this a pairing off? Can Microsoft with RIM compete with Apple and Google in the long run? I'm not sure buying RIM is enough. Google appears to be getting into the phone business as well. Think Gmail messaging on a Google platform funded by the Google ecosystem.