There's a balance to be struck.
Most people will not be able to retire at 40 with £1m however much of their salary they are able to save.
But it's not the "coffee a day" culture that does stop the saving. It's the coffee and packed lunch, and the couple of foreign holidays, and I must get that new car, the iphone and have a gardener and a cleaner and that dress has a tiny rip so I'll throw it and buy new...
I'm not saying that any of those things on their own are frivolous and prevent saving. However they all add up, and I think there is a culture that does say "you deserve these things, you shouldn't have to go without any" - and then is surprised when there's no money left.
I remember explaining to my dc when they were quite small that when I said we couldn't afford something, it wasn't that we physically didn't have the money for that particular thing. But that if we chose to have that, then we couldn't have something else which we might want more. Did we get the Merlin Annual passes, or did we go on our annual holiday to Butlins? Unanimously chosen the holiday - they understood that they couldn't have both.
And I think one thing that has produced this attitude is the lack of opportunities to have the choices. When I went on school trips, I had my 50p to budget, and no more. I would try and buy something for my siblings, and often it involved me walking round the shop thinking "if I get the bigger rubber for dbro, then I can only get the ruler for dsis" and things like that. My dc when they went on school trips had none of this - they would all get a badge bought by the school.
Equally well the school tuck shop: shall I get the 6p packet of crisps and then I can get 4 penny sweets, or the 8p drink and save the other 2p and have more tomorrow?
I think this has effected the current generation in that they don't have this opportunity at a young age to realise that 50p spent now means no 50p later.