Portability, robustness, flexibility and security.
There's little reason to spread out a package like meteor all over /usr/local. But many reasons against doing that.
To illustrate, a few simple questions:
What if I need multiple meteor versions on the same system (different versions for different users/projects)?
How do I quickly switch between different meteor versions (often needed in fast-moving projects like this)?
How do I monkey-patch meteor to try something out and/or contribute back?
What if I absolutely must mix meteor with an unsupported version of node or other runtime dependency?
What if all my servers are SuSE Solaris95 but you only provide packages for Debian and RedHat?
How do I bundle my meteor runtime with my deployment?
I agree with all of this :) Meteor is self-contained and installing it in /usr/local is totally optional. The reason we install into /usr/local is that it is a way to get the 'meteor' command into the user's path without trying to edit their dotfiles for them, and without setting obscure system preferences that the user would have trouble unsetting. We went to a lot of trouble to make it easy to try Meteor, and we thought that "great, now go edit your dotfiles" would have lost a lot of people.
If you don't want it in /usr/local, you can check it out anywhere you like and just run the 'meteor' in the top directory of the checkout, and it'll work great. This is mentioned in the README/on Github, and it's how we have been developing Meteor. You can have as many copies of Meteor on your system as you like, and they can even coexist with a copy at /usr/local. So for me, I type '~/co/meteor' to run the meteor that I'm developing on, and 'meteor' by itself to run the latest official release.
You can either build the binary dependencies (node, etc) yourself by running an included script, or if you do not, the first time you run meteor it will automatically fetch a prebuilt binary kit for your convenience. All of the binary dependencies are kept in a directory in the checkout and managed by meteor, meaning that each meteor install on your system can have its own version of node.
Finally, to your last point, 'meteor bundle' does exactly that :P In fact, right now on our deploy servers, we have live apps running that were deployed with a variety of historical versions of meteor, all coexisting side by side.
I'm sure we'll have to revisit all of this as the Meteor ecosystem gets bigger and more complicated -- when all of the packages do not fit in a 'packages' directory, and when there are more binary dependencies than node and mongo. But I hope that this helps to persuade you that we're not totally nuts, despite how sleep deprived I was when we recorded that screencast.
If you thought this was a helpful answer, could you repost the question on Stack Overflow (with the 'meteor' tag), and drop me an email (address is in my HN profile?) That way I could repost this answer there in case it might be helpful to other people.
I agree with almost everything you say; you seem to have it right then, I just didn't go through github so I never saw the README.
However, I would still argue that you should get rid of the packages, that's extra-work you could better spend elsewhere. For someone installing a dev-toolkit it's absolutely not too much asked to paste "echo >>~/.bash_profile 'source ~/.meteor/magic.sh'".
They have to do that anyway as soon as they need the latest git-HEAD because of some bug in the release version (we know how it goes, don't we? ;-)).
So by giving them the right instructions right away you save them this extra step. And you save yourself from making a bad (and false!) first impression on the older and grumpier devs like myself.
I am definitely not in favour of piping curl output to sh and giving root access.
I do prefer packages installed to /usr. You can easily solve the multiple-version-problem: Debian/Ubuntu has `alternatives`; Gentoo has `eselect` etc.
With these tools it is easy to "slot" packages (Gentoo terminology): /usr/bin/meteor would become a link to /usr/bin/meteor-0.1, /usr/bin/meteor-0.2 or whatever. And it is selected by the `alternatives`/`eselect` commands.
And how do you bundle your runtime? Just install the darn package!
If you are using SuSE Solaris95 and all your software is packaged for Debian or RedHat, then you should consider switching to a distribution that makes it easy to install third party software using the native package manager. If that means building a deb or rpm, then so be it; it's not that difficult.
To illustrate, a few simple questions:
What if I need multiple meteor versions on the same system (different versions for different users/projects)?
How do I quickly switch between different meteor versions (often needed in fast-moving projects like this)?
How do I monkey-patch meteor to try something out and/or contribute back?
What if I absolutely must mix meteor with an unsupported version of node or other runtime dependency?
What if all my servers are SuSE Solaris95 but you only provide packages for Debian and RedHat?
How do I bundle my meteor runtime with my deployment?