If you follow me on Twitter (@drewmccormack) you're probably a little sick of my postulations about the future of the Mac. I've been thinking a lot about it lately, trying to decide what it all means for the future of software. Is the Mac still a viable platform to develop for? How long will it stick around? These are the questions that keep me awake at night.

So here's the evidence all in a row:

1. 1)When asked about the future of Macs and PCs at the recent D8 conference, Steve Jobs said they will become like trucks (Mack trucks?), specialized devices used by the few, rather than the many.
   

2. 2)When Apple introduced the iPad, they also introduced iWork, a clear message that the iPad is also intended for content creation. (I'm typing this post on an iPad.)
   

3. 3)Apple introduced iMovie for the iPhone at WWDC. The iPhone now has most of the iLife apps in some form or another. Again, the message is that you can do serious content creation on the touch devices.
   

4. 4)For the first time ever, Apple did not present any design awards for Mac apps at this year's WWDC.
   

5. 5)Last financial quarter — before the iPad was available — only around 15% of Apple devices shipped with Mac OS X installed.
   

6. 6)In the first two months after its release, iPad sold at a rate faster than the Mac.
   

7. 7)The App Store already has many more quality RSS readers for iPad than the Mac ever had.
   

The biggest worry for the Mac, in my view, is not lack of revenue or market share, it's lack of consumer software. The missing Mac ADAs were probably not a deliberate snub of Mac developers by Apple, but rather a genuine fear that they wouldn't be able to come up with 5 decent candidates this year.

Contrast that to the situation on the iPhone, and now the iPad, where any attempt to select a design award winner from the thousands of worthy applicants is bound to end with the words "Eeny meeny miny moe...".

How long can the Mac, in its current state, remain a serious option for the consumer? If you ask me, not long. I think we will start to see a serious shift to the iPad over the coming year, simply because when you weigh the availability of quality consumer apps on the iPad against those on the Mac, you would almost have to be crazy to go with the Mac. And the fewer consumers opt for the Mac, the fewer developers will develop software for it, compounding the problem further. This descent could be very fast, perhaps spanning the standard computer upgrade cycle of about three years.

The Mac may look like a Mack in just a year or two, but it won't die immediately, because there are still many professionals who rely on it, and there are apps that simply don't translate to the iPad. But ask yourself this: Do Apple really want to sustain a whole separate OS and set of development APIs for a product that perhaps accounts for less than 10% of it's hardware sales? Questionable.

Even if the Mac does survive in its current form, if you are a developer of consumer software like me, I suggest you start working on your Cocoa Touch chops. The Mac will be used by professionals in professional environments, and the market for consumer software will be lean to say the least.

Apple could do a few things to give the Mac a reprieve ... if that's what they want. They could introduce an App Store for the Mac to encourage development on the platform. In my view, the decline of the Mac that I foresee has more to do with a dearth of consumer software, rather than the more obvious differences in user interaction.

Another way that the Mac could get a reprieve is if Apple made porting iPad apps to the platform as easy as porting between iPhone and iPad is now. At present, the Mac shares very few APIs with its touch cousins, outside of low-level data handling. If Apple were to integrate UIKit into the Mac in some way, many developers would be tempted to support the platform. This may also provide a gradual transition to the eventual merging of the platforms.