There's a whole army of photographers (on this forum and elsewhere) who were producing good work before image/lens stabilisation was ever introduced. So 'no', not strictly 'necessary'.
In the same vein, all you really need is a sensor, lens, and shutter (+ some control device/circuitry) in a light-tight box. You don't NEED a LCD display, auto-aperture, autofocus, auto exposure, in-finder displays, etc.
Like all these other features technology has added to our tools, it can be very useful. And it can open up new possibilities and opportunities that just didn't exist before.