Speakiing as a kid made to dress up as 50p at a school fete in 1971, I think Decimalisation coincided with high inflation and gets too much blame.
My other recent thought is about something that happened around the same time as EEC membership and went the same way: The reorganisation of local government, in particular the Metropolitan Counties.
There were good solid economic planning reasons for arguing that instead of seeing esturies as boundaries, they ought to be placed at the heart of local authorities responsible for services on both sides.
But Avon, Cleveland, Tyne & Wear, Merseyside and, most of all, Humberside, were unloved and never gained popular support. They got the blame for things they never did, were subject to local media disinformation campaigns, and in the end bit the dust, much like EU membership, for a more parochial version of the same reasons.