Simply put, this is generally a good idea. Funding start ups which are creating applications, particularly those exclusive to the Mac, would be a powerful move from Cupertino. Backing innovative developers who work exclusive on MacOS X with the tools, systems, cash, contact with Apple internal developers, debugging assistance and distribution would be HUGE. New applications, especially those which can't be found on other platforms, would help drive the Mac into new niches. (And the Mac is the ultimate niche platform, but add enough niches together and you have a real market.)
Even bigger though, and with a bit less headache, would be just to seed application developers.
As the BusinessWeek piece mentions, plenty of small developers (and large ones too) do not release Windoze and MacOS X versions of their apps simultaneously. The biggest reason is that the development costs involved in development, QA, documentation, distribution and all the other functions of software creation comprise a much larger portion of the potential revenue to be generated, at least on the Mac. There just aren't as many systems in the field to amortize the development costs over.
Apple could be using strategic investments in the $5M - $50M range to seed development of a wide range of apps from developers large (Adobe and Microsoft) and small (Delicious Monster).To me, the most critical issue would be to fund developers to port applications that only run on other platforms to the Mac. In the case of apps that run on Solaris, HP-UX or other commercial *nix variants, this could be enormous. The Mac is THE Unix platform to develop on. Apple has the momentum, the cash, the installed base and the platform to allow finance, visualization, and scientific/engineering/mathematical developers even broader outlets for their applications. That's some real value add, IMO.
The point is to increase the size of ecosystem and to build better developer relations with the members of that ecosystem. Apple has historically been very bad about this, and that tone continues even to this day for some God-awful, unknown reason.
People buy computers because of what they can do with the machine. Simple. So the more things that can be done on the Mac, the larger the potential customer base. I for one would love to have a real, complete Visio running natively on MacOS X. Hopefully Apple will learn this lesson and start seeding developers who are creating apps that people want to run on MacOS X. This is a mistake SUNW made back when they had a war chest, and the results are pretty obvious.
Whether creating a VC arm is the best use of Apple's cash is debatable. However, putting some of that cash to work in developers who can expand the user base of the Mac platform is a no brainer. I just wonder why it hasn't happened yet.