I stated in another thread, and believe it makes sense, that even though 2.1 might be ready to roll for Droid, VZW/Moto aren't doing it because of one thing....
Google just launched the Nexus One, with Android 2.1 on it. Right now, sales are not that great, and from what I have read, the N1 is having some issues with it's OS. It makes sense to me, that Google is not allowing updates to the Droid/Eris right now, because they want to get 2.1 straightened out for their "flagship" phone. The N1 is Google's, HTC may have made it, but it was designed, from what I understand, by Google, for Google, to promote their "Google Experience" as it were. Yes, the Droid is a "Google Experience" phone, but, the Droid was build by Motorola without as much input from Google. T-Mobile provides the network, and the marketing, but Google stands to profit the most from this phone proving to be popular. Updating the Droid, an already stable device, as well as the Eris, with a good customer satisfaction could direct sales away from the N1, and to the pockets of VZW/Motorola more so then themselves.
A consumer looking for a smart phone, might consider a Droid with 2.1 over an N1 with 2.1, because the Droid is more stable, and the N1 has been having some trouble. Believe me, when I was making a decision on which phone I wanted, I looked at everything VZW offered, not just the Droid, and weighed pros and cons, read consumer reviews, and well as tech reviews on the devices, and ultimately decided on the Droid. Almost anyone will do that, because people by smart phones because they want the productivtiy/organizer benefits that come with it, and if they are going to plunk down a couple of hundred dollars for a device, they are going to make sure they are buying the one that will work best for them.
So, if the N1 is having issues, and Google allows the "competition" to be upgraded, they are cutting their own throats, in a way, because they then would be taking the focus off of their "flagship". Google has an interest in the Droid, and the Eris, they helpled develop them, but the N1 is their baby, and they are going to want it to succeed, so if that means letting Droid owners hang a bit while they stabilize 2.1 for the N1. When they get bugs ironed out, complaints go down, and sales go up, they will release the 2.1 to the rest of us.
Start thinking late spring, early summer....