As in economics, the generic drivers are: lock-in, positive feedback, increasing returns (the more a choice is made the bigger its benefits), and self-reinforcement (which creates forces sustaining the decision).
The inclusion of these generic drivers allows for faster deployment of devices and easier installation by end-users.
At least the generic drivers for Ubuntu tend to actually let you get online.
An operating system is supposed to implement all device classes, so it can provide generic drivers for any USB device.
It connects over an IP Address using a standard protocol (IPP) and uses a single, generic "driver" and that was 6+ years ago.
Other operating systems may have support in the form of a generic driver that lacks complete support for the hardware.
Today, third-party generic drivers are available as freeware for Windows 98 and Windows 98SE.
Windows 2000 has support via a generic driver for standard USB mass storage devices.
I'd *love* it if all the different printers I support could speak one of the two and get at least basic functionality with a generic driver, though.
I don't think a generic driver would work.