I think Palm's only chance would have been to join Android and use it's well known name to enable a common extension that allows more for developers.
Android's goal is to make it compatible with about everything, so applications are in Java (or, iirc, another, propietary, bytecode) and thus limited to their sandbox. System extensions we love on our WM devices, like today plugins, launchers, WBA & Co., and the like are probably impossible (unless they've got really a huge API and are going to force manufacturers to use 2GB RAM and 600MHz for their devices...
) or limited to a very small number of devices.
So if Palm could establish an unified extension, like e.g. Nokia did with Series60 (and follow-ups) as extension of Symbian, it might get some success... (Given the Android license would allow that...)