To go off at a slight tangent (sorry). If you fast forward to the late 90s/early 00s, wasn't there something similar, perhaps not quite as drastic though, going on?
The old BR many had come to love was being broken up into lots of little businesses, loco haulage was being discontinued as quickly as possible. 47s on Cross Country services replaced with Voyagers, 37s in North Wales replaced with 175s, units everywhere you look. The old order (20s, 37s 47s, etc) in freight haulage being displaced by the 'Red death' class 66s.
I was around at the end of steam, it was a very sad time, I lost interest in railways for several years, but came back. I followed the last couple of years on the North Wales Coast with 37s, then 47s as the units simply weren't reliable enough. Put in a few trips to South Wales as well, 37s, then 50s, a type I'd never bothered with before.
I think that a lot of the apparent resistance is down to a dislike of change, which is mostly, if not exclusively, driven by financial factors.
The next big change to come, and come it will, is the replacement of the HSTs and older DMUs. IEP anyone? The last true loco operated service (GE main line) may well I suspect be unitised fairly quickly when the new (long) franchise starts. Who, in 1975 or 76 would have expected people to be getting nostalgic for the HSTs, it was bad enough replacing the Valentas with MTUS!!
That will provoke similar reactions to all the previous changes, but it'll go ahead because most of the fare paying passengers don't give a rats*ss what kind of train they're on. So long as they get where they want, when they want it's OK.