Will the panda3D drop development for other platforms than windows?
The core Panda3D code is actively developed on both Windows and Linux. At the Walt Disney VR Studio, we use it on Linux every day. Panda3D was actually developed first on SGI, then ported to Linux and only to Windows third.
However, the Linux platform is not supported by the CMU team, meaning you are on your own to obtain the source code and build it yourself on Linux.