WHBM -
My post was really referring to sentiment, rather than factual analysis. It was the press that found the 'link' between these two incidents to have been the elderly airframes involved. Whilst I agree that the other factors you mention were instrumental in the change to jet fleets, I still feel that weekend in June 1967 changed the way the public felt about 'old' piston-engined aircraft.
You also mention that British Eagle's demise removed a number of Britannias from the market. On the contrary, those aircraft were bought by the likes of Monarch, Lloyd International and Donaldson who continued to fly them on IT charters, although not for many years.