When predicting the demise of the revolver we all must keep one very important consideration in mind.... That primary consideration is the much more powerful calibers available in the revolvers not possible with the plastic guns...
When comparing the 9mm, 40S&W, 10mm and 45acp plastic gun calibers to the revolvers .357, 41mag, 45 Colt, 454 Casul, 475/480's, 500, etc, etc, the future should remain bright for the revolvers.
I own many of both type guns. In fifty years I expect current production revolvers to still be functioning and selling strong...and current production plastic guns to become .... well ... throw-away.
Just say'in.....