The announcement accompanied a particularly bloody quarterly report, which is perhaps why Palm felt it necessary in the first place—when you're hemorrhaging money, it's best to assure investors and analysts that you're not putting all your eggs in one Pre-shaped basket. This was, however, pretty obvious all along. Palm is a handset maker first and foremost, so they were never expected to adopt a one-OS, one-handset strategy like Apple.
More importantly, when Palm says they plan to expand WebOS "well beyond our [Pre]base," it conjures images of a better time, that golden Treo heyday when a rich line of great handsets were united by a fantastic OS, and the name "Treo" had serious cachet. So 2010 is the new 2003, or something. [CNET]