I suspect the insulated pins were introduced because the recessed sockets were a flop when they tried to introduce them, given the amount of plugs, double adaptors and plugpack transformers that wouldn't fit into them.
It's not just the flimsy pins on the plugs now, but the flex attached to most 2.4KW appliances in recent years is underrated and becomes too warm for my liking. Proper 1.5mm flex and a chunky old stock bakelite plug fixes the problem.
As for the new plugs I usually end up bending the pins just pushing the covers on they're so weak. Anyone from this part of world will know of the force required to push the cover over the part with the pins and terminals when connecting a plug.
The story I heard re the introduction was that someone with a chain around their neck leaned over a GPO and it went in the gap touching the live pin. Apparently this person was some big knob somewhere who had the necessary influential powers to get things changed. Could be an urban myth of course.
