Intelligence certainly has a practical threshold. If you have no intelligence at all you cannot thrive in a world of computers, pens, clothing, dishwashers… On the other hand, technology has allowed some areas to lower their intelligence thresholds. People who have severe mental disabilities can function in relatively normal lifestyles.
I’m not sure what you mean by “relatively normal”. In countries like the UK and USA, about 20% of the adult population are said to be functionally illiterate. In a world where a normal lifestyle is rapidly coming to include using the internet, where applying for entry-level jobs can only be done online, these people are going to have major difficulties coping. This may well be a significant social issue in coming decades.
Sure. What’s not rational is to believe that politicians will deliver on the promise of reducing waste. All politicians say they will do it, and have done for a long time, but governments are not noticable less wasteful than they were 50 or so years ago.
It’s therefore irrational to believe a politician when they say they will cut waste, unless they say in detail how they will do so (which they usually don’t).