Can a python script on my server access the webcam and audio input of a user as easily and as well as a Flash plugin can?
['https://Stackoverflow.com/questions/2926220', 'https://Stackoverflow.com', 'https://Stackoverflow.com/users/301860/']
No: the "plugin" you mention runs in the user's **browser**, your server-side script (Python or otherwise) runs on the **server**, a completely different proposition. This relates to your other recent question about a server-side script accessing information on your desktop: your client machine tends to be very protected against possibly malicious server-side apps (never enough, but everybody keeps trying to make it more and more protected these days).
Not as easy, no. But there are extensions you can use. E.g.

A Win32 Python Extension for Accessing Video Devices (e.g. a USB WebCam, a TV-Card, ...)

<http://videocapture.sourceforge.net/>

Tutorial:

<http://technobabbler.com/?p=22>