10.4 this year? Look at the pattern
People often overlook two things when they complain that Apple advances Mac OS X too quickly:
First, regarding cost, $129 is NOT "full" price, it's an upgrade to whatever version of Mac OS (8? 9?) you already own. Some expect OS X should ship at two different prices--like a new version of Photoshop or Office--but that would only make sense if there were buyers who did not ALREADY own Mac OS. Apple has never sold Macs without Mac OS, so there IS no "standalone"/"first purchase" price for OS X. Everyone's first Mac OS purchase is simply bundled WITH a Mac.
Second, regarding timing, OS X was a new OS, and thus subject to faster improvement and more frequent upgrades. That's very desirable in a new product! But the update rate slows down over time--and that's clearly been the case with OS X:
Mac OS X Public Beta: 9/13/2000
$30 (free shipping, like all versions), all credited towards purchase of 10.0.
...6 months...
10.0 Cheeta: 3/24/2001
$129 upgrade from all earlier versions of Mac OS. ($99 for Public Beta users.)
...6 months...
10.1 Puma: 9/29/2001
Free to 10.0 owners, $129 upgrade from earlier versions. Given away at CompUSA and other stores. (Mac users who have been with OS X from the beta days have still only paid for it once.)
...11 months...
10.2 Jaguar: 8/24/2002
$129 upgrade from all earlier versions of Mac OS.
...14 months...
10.3 Panther: October 10/24/2003
$129 upgrade from all earlier versions of Mac OS.
...more than 14 months?...
10.4 ?
So the upgrade cycle, in months, has been: 6 - 6 - 11 - 14 (with two free versions early on). Apple's rate of change has naturally slowed as the OS has matured.
Panther took 3 months longer than Jaguar. What if 10.4 takes 3 months longer ( 17 months) than Panther? 10.4 would then be released in late March 2005. Or if development STOPS slowing down and 10.4 only takes 14 months again... that's still late December 2004. So even if 10.4 takes the same or slightly less time than 10.3, Apple might still wait a few days to release it in 2005. That would please the vocal people who think Apple should move slower: there would be NO paid releases in 2004.
And remember that earliest reports of a new Mac OS often come out FAR ahead of the shipping product. So I think early 2005 is very likely for 10.4.