Past conditionals obviously can’t be disregarded. In most Latin-origin languages, these verb forms and endings are often extremely difficult and a major hurdle for foreign learners. Italian past conditionals are particularly difficult, yet Italian culture seems to have maintained a high regard for the need to drill in this verb form to students at all levels.
In English, the problem isn’t structural: the past conditional is pretty standard. You get “if I had (or hadn’t)…, I would (or wouldn’t) have …” As in “if I had taken that job …. I would be rich today”, or “if I hadn’t married X , I would have been happier…”. You can play around, put in any verb you want.
But whatever the language, the problem isn’t really structural, it’s a psychological and often cultural “game”, and some cultures are more unfortunately prone than others to using this type of utterance. On the upside, offering up past conditional sentences is proof of a sophisticated mindset that us humans have evolved thanks to our developed cognitive abilities. They allow us to play with reality, to look back and imagine a different past, which would presumably have led to a different, and happier – or more satisfactory, or richer or whatever… – present.
But the past is over, good and done with, and revisiting it with an “if” keeps us from fully acknowledging the place we’re at now, or worse, keeps some people in a vicious circle of wishful thinking and regrets.
Listen to someone embark on a past conditional sentence: can’t you just hear it announcing, more often than not, vague and often cyclically revisited pain? Doesn’t it make one wonder why, with the superb tools evolution has given us, we still play around with language, concepts and past-oriented thoughts that only hold us back?
When I’m teaching languages, I obviously do “past conditional” with students, but when obliged to, I hurry along and move ahead to other more positive items (hey, how about some futures?) as quickly as possible. If they haven’t quite grasped the form, I just tell them no worries, move on: past conditionals are of very dubious use to anyone anyway.