xphile makes a great point - there's a lot of rhetoric about Linux: The Alternative OS, but from the a home usage or business productivity standpoint the Mac is a much, MUCH more appropriate Microsoft alternative.
I think one big reason that you don't <b>tend to</b> see journalists touting the Mac's potential as a Windows-killer or Windows alternative (there have been a few in the last year) is because they're afraid of rehash - that is, "alternative" has been the Mac story since the beginning, and even up until the last year there's been little <b>new</b> to report about, OS-wise, from year to year (though I think journalists have been consistently, if not happily reporting Apple's biggest successes, i.e. the iMac, etc)
Linux is a platform whose popularity came about in part riding on the back of the Internet boom (some would argue that the reverse is true). Its popularity with "geeks" is one of hundreds of factors into its success, but when it comes down to it, its popularity is mostly based on its main revolutionary feature: It's FREE. (Again, some would argue with just how free Linux is) Yes, it is possible for me to build a 1ghz, reasonably loaded Linux box for $350 (sans monitor), and have it running with a full office suite, web server, mail server, etc. etc. (I know Apache's been ported to OS X, most Macs are bundled with iMovie, AppleWorks, etc., but for $350?)
From the journalists' perspective, Linux is (relatively) new to the market at large, doesn't require a huge investment to try, even on existing machines (Apple included), and due to timing and tto the crowd that most helped push it into the initial, peripheral view of the world (the "geeks") became synonymous or directly associated with two other huge buzzphrases of the last few years - "open source" and "Internet".
Apple's MacOS releases have been excellent, steady, but little innovation took place in the OS over the last 15 years. The Mac has always remained an excellent workstation and home computing platform (and Windows alternative), but, especially 1995-2000, Apple introduced very little to give journalists an excuse to revive the old "Mac vs. Windows" debate (we're talking about the CNBC, CNN, Wall Street Journal folks here as well as the computing mags, which are at least as important to the discussion these days as the industry mags, since Joe Web Surfer/Jill Email Jockey is NOT likely to be a computer buff (and get all their computing news from the 1 minute nightly spot on the 11 o'clock news), but are certainly computer consumers.
I do think, however, that talk of Apple dominating the market is scarce for very good reasons. For Apple to "topple" the Microsoft empire would require one of three things: 1) Continuous erosion of the Wintel empire, 2) New Disruptive and Revolutionary technology, or 3) Disaster in the world of Microsoft/Intel.
#1 is the most likely to ever happen in this case, and could happen with a string of clever moves, innovative products, good marketing, etc., but will require a LOT of things going right for Apple, some things going wrong for M$, and a lot of time.
#2 - The last time Apple was poised to dominate based on revolutionary technology was 15 years ago, with the introduction of the Mac. At the time, Apple offered home users a computing experience that was unavailable with any other platform (and often superior). X was still in its infancy (Unix workstations in the home were almost unheard of, anyway), and Windows 3.0 was years off (1990). WYSIWYG, OS usage simplicity (no editing config.sys to install extended memory drivers, no config "tuning" to squeeze more free memory into your base 640k), and other features offered a <i>drastic, and obvious difference</i> to users desiring the features. In the end, cost of the machine, difficult software development environment, etc. slowed Mac acceptance until M$ was able to release products more closely simulating the Mac "experience", and taking away one of Apple's major advantages. M$'s existing dominance, some platform advantages and poor (anti-competitive) business practices allowed it to continue to erode the market, despite Apple's obvious strengths in many areas.
Subsequent releases of MacOS continued to strengthen the Mac as a platform and OS, but very little "revolutionary" has been introduced from rev to rev - There was never again a point where the Mac was the "only" platform for a genre of apps (certain markets, yes (graphic design, etc)), and its ability to distinguish its advantages from the PC have slowly shrunk.
Flash forward to today: OS X is a revolutionary OS for the Mac. It's a wild (and much-needed) swing from the previous line of OSes. After passing its infancy I expect it'll be a VERY strong OS and home computing platform (if it's not already!). However... Is it a Revolutionary OS for computers in general? Discounting some of the soon-to-be-eliminated shortcomings, from the perspective of Joe Home User, are Mac OS X and the Mac able to provide a revolutionary experience - one unavailable to users otherwise?
I say no. Don't get me wrong - I love OS X. It's a great mix of Unix, kick-ass GUI, sleek design, and most of the best elements of previous versions of MacOS that has kept the platform alive for the last 15 years. But from an industry standpoint the Apple Experience still isn't enough to distinguish it from Wintel. There is VERY little that I can do on the Mac that is unavailable to me on my PC. The experience is BETTER in a lot of cases, but that's been the case with the Mac for much of the last 15 years, hasn't it? The innovation of OS X, the hardware, the physical Mac design, and the apps (to an ever-lessening extent), and the fact that Apple <b>isn't</b> Microsoft certainly are enough to distinguish the Apple as a Personal Computer, and in the past few years this has been able to attract a lot of the brightest, most creative folks in the industry. However, the money is in the mass market, and to combat market ignorance, reluctance to change, and the certain drawbacks of the Mac platform (I know a die-hard is going to yell at me for this, but yes, there are some...)Apple <b>needs</b> to be able to clearly distinguish the advantages of the Mac platform to the home consumer, business production, and educational markets. However, even with the current product set, I don't think this is possible, and the hurdles are still to high. Even further innovation and a "killer app" or two is going to be necessary to bring back the Mac as a big player in the mass market. Either that, or a lot of hard work, excellent decisions, and a bit of luck