Palm didn't have anything to do with Palm OS 6, they spun off Palm OS development to a company called PalmSource (later ACCESS). Palm OS 6 was finished around 2

Palm didn't have anything to do with Palm OS 6, they spun off Palm OS development to a company called PalmSource (later ACCESS). Palm OS 6 was finished around 2004, but never shipped on a device because the performance was horrible compared to Palm OS 5. This was due to poor software architecture. PalmSource threw out the kernel used by previous versions of Palm OS and replaced it with a microkernel that focused on message-passing between processes. Most of the Palm OS API got re-implemented using IPC. This meant that each API call would require at least two context switches, more if the API implementation needed to make another API call that was implemented with IPC. The ARM chips that were available at that point flushed their caches on each context switch. The result was that doing something like opening an address book with around a thousand entries went from taking a few hundred ms to taking seconds, as displaying each entry required an IPC call to the service responsible for handling contacts data. It's definitely a shame, as Palm OS 5 is a stopgap OS that got shipped on devices way after the point it became obsolete. Third-party developers couldn't even write native ARM software, they had to compile for 68k and add small chunks of ARM code for performance intensive areas where the 68k->ARM emulation became a bottleneck.