There are two problems with your approach to things:
1) If we keep saying "not everything is ready yet" then you'll never reach a point where we are using 64-bit. Companies have no incentive to release the software unless they are effectively forced to. Microsoft's approach has a lot of problems, but it works for the most part and they've got three pretty good 64-bit OSes out there now.
2) The issue isn't that the 64-bit kernel is disabled by default, it's that it has been COMPLETELY disabled on certain models of computer when there is NO valid technical reason for doing so. My MacBook can run 64-bit software just as well as any other 64-bit Mac, yet due to Apple's marketing crap it's intentionally crippled.
To suggest that a software update will correct this is laughable, purely for the reasons you've outlined. People don't expect an update to remove compatibility with their hardware and software. An OS Upgrade is different to an update. I expect fewer things to work with a new OS, but I don't expect anything to stop working after a simple point update Like (like 10.6.1).
Well, the point is, is that WE WILL move to 64-bit. This version is technically forcing all developers to move 64-bit. Why else would Apple advertise this as 64-bit? Apple's approach is better than MS, strictly because of the way they designed OS X from the beginning. You may think that since MS had two different versions of Windows in 32-bit and 64-bit fashions, that it would force more developers to make more software in 64-bit. But we still haven't seen much software that's 64-bit, even on Windows, which has had 64-bit LONGER than OS X. The 64-bit kernel really has nothing to do with developers producing 64-bit software.
Apple wants to make sure MOST of the software currently available will run with few or no problems at all, hence why they probably enabled the 32-bit kernel at default. Remember, MOST consumers aren't as tech saavy as we are, so what happens to them if Apple enabled the 64-bit kernel at default, and they were running in several problems with driver issues, etc?
And yes, I understand everyone's point about not being able to boot the 64-bit kernel in certain configurations. I imagine Apple will eventually provide either a firmware update + software update, or one or the other. Just be patient, and things will eventually come together. It's not like Snow Leopard is any different than Leopard anyways. It looks and acts like Leopard, with a few improvements under the hood. That's it.
I'm gonna laugh if you're one of those people who has a Macbook or iMac that can only take up to 3GB of RAM, and you want 64-bit capabilities. Well uhh, it's silly because these machines can't address more than 4GB of RAM, so it doesn't really matter if it's 64-bit or not. Yes, there may be improvements if 64-bit software uses the extra registers. Snow Leopard at this point is really only useful for recent Macs have max RAM of up to 8GB (iMac/Macbooks), or the Mac Pro. Anything before that, pointless.
