Both phones are listed as limited, with no remaining shipments from the vendor, Motorola. It is not known what the inventory levels are for either device or when they might be completely gone. This is not to say the phones won't be supported with future updates, just that they're nearing the end of their life cycle. Motorola has at least pledged Android 2.2 for the Droid, while the 2.1 update for the Devour is under evaluation.
The demise of the Droid shouldn't come as much of a shock, as the Droid 2 is expected to arrive in coming weeks. Although Motorola has had a solid run with arguably the most popular Android phone to date, it would be hard to keep selling it with its successor sitting on the shelves next to the Droid X and Droid Incredible.
It's a little more difficult to say just how successful the Devour was for Verizon. In the few months since its release, I have yet to run into anyone with the entry-level Motorola device.
It's worth noting that neither the Devour nor the Droid were listed in the upcoming summer catalog spotted a few days ago. It wouldn't surprise me to learn that Verizon had planned for quite some time to phase out the Droid. I imagine the carrier worked closely with Motorola on sales and shipments to make sure it didn't end up with too many Droids sitting around or, worse, not enough Droid 2 phones.