You still can install whatever you want on the phone. You just need to jump through a few (very minor) hoops to enable developer mode.
The Palm Pre has a thriving homebrew community of hackers who have done exactly this, and have written over 250 apps that don't go through the standard Palm app store and can be installed just by a normal download link.
Palm devs have even been following the homebrew community closely and invited many of the developers there to offer their apps through the official app store as well as through the homebrew scene.
The Palm Pre has a thriving homebrew community of hackers who have done exactly this, and have written over 250 apps that don't go through the standard Palm app store and can be installed just by a normal download link.
See: http://www.precentral.net/homebrew-apps
Palm devs have even been following the homebrew community closely and invited many of the developers there to offer their apps through the official app store as well as through the homebrew scene.