not to forget that this is an Open OS. There is no license fee, and manufacturers are free to dig into the guts of the OS and do some fancy shit.
If it's branded a "Google phone", like the G1, and the Moto Droid (and I think one or two others), then Google worked directly with the manufacturer/carrier and the OS experience is what Google wanted. But otherwise, it's a free for all.
It'd be nice if Google was a little selective and said
"these hardware configurations are required if choosing to use the Android platform", so that developers have common ground to help make developing apps for multiple phones just work, versus crashing on some phones and other phones running perfect. But ultimately, for us techies, it's going to be communities based around specific phones, compiling apps geared toward those specific phones. And this is basically how it is already, and the Droid is getting a massive developer following as the user base is just expanding massively. Which is awesome, that means I have a phone that will get a lot of detailed attention from developers.
This is similar to what WinMo communities were like. Everything was geared toward specific phones and their hardware, so getting apps that were made for other phones was just a gamble as to whether it worked or not.