I disagree with almost every point. Palm had flash memory, color screens, and wireless before, or with, everyone else. (I do concede that they made incremental hardware "improvements" with every new Treo, instead of researching and adding innovative features.)
On the other hand, Palm did not add features to their operating system for what must be 7 years now. They did go up a version by adding 320x320 resolution support, but it was more of a hack than anything else. Each individual component (app, database) was still limited to 64k in size from what I recall. Palm was run by business people (more so than Android and the iPhone have since) who thought incremental updates of screen and camera resolution and doubling the onboard memory from 32MB to 64MB were good enough improvements each year.
Palm also did not have a Blackberry-like push e-mail app until maybe two years ago (and even that was because of a third party e-mail app; the default app that Palm owned and installed with every Treo did not even support IMAP.) But around the same time as adding IMAP support by purchasing the rights to a 3rd party e-mail client, they decided to start supporting Microsoft Exchange and running Windows Mobile on half of their new devices every year.
What happened? Apple fans originally loved PalmOS because it wasn't Microsoft. It was based on Apple's Newton. Secondly, the Palms worked better with Apple computers than Microsoft's devices did. Third, supporting the Palm could prevent Microsoft from dominating the mobile world on top of the PC world. Finally, Palm "sold out" and went with Windows Mobile, instead of improving or rewriting their aging operating system.
With the iPhone, Mac lovers could now get a real, current Apple product. I think that was the greatest gift to Mac users and Palm fans who were getting sick of Palm's insignificant incremental improvements.
Now if by software you mean the freedom anyone has to write and distribute a 3rd party app for a Palm device, then yes, they are still the easiest to release apps for. A developer doesn't need anybody's permission except that of the user themselves. But as far as the software PalmOS created and owned--such as the operating system and mail client--only minor improvements were made over the past seven years.