There completely different situations. While the wars were undoubtedly horrific they also brought a sense of purpose and unity. Many young men were only too eager sign up and participate in what they believed would be a big adventure.
After the wars there was huge amounts of rebuilding to do again giving purpose.
My grandfather, for example, left school at 14, joined the war effort at 18, survived and secured a job as a mechanic on his return, this job allowed him to purchase a 4 bed detached home off the bat where he raised his family and progress through the company to a management position, which gave him a great pension when he retired at 60.
My father left school at 16, walked into an apprenticeship with British Gas and stayed their for his entire career, again progressing through the ranks.
His job allowed him to buy a starter home, upgrade to a family home when I came along, and again to a larger family home when my siblings came along. It also allowed him to support my mum through university, take us on holidays, and gave him good pension when he retired at 63.
I left school at 18 initially took a trade but retrained as there wasn't room for progression and now have a degree and a masters. I was only able to buy my starter home in my 30s, can't afford to upgrade from here, can't afford to reduce income to have kids, can't afford to support my partner to retrain from a job they hate and is slowly grinding them to dust, and despite progressing through the ranks a bit now I'm no better off than I was 10 years ago. Oh and have a shitty pension that means I'll probably have to work till I die.
As others have said its the relentless bleakness that crushes us and there is no light at the end of the tunnel, things are only going to get worse.
I have tried to end my life before and I'm only still here because someone spotted what I was doing by chance and alerted the police. I flick between just accepting the drudgery of life and thinking about flinging myself off a bridge to get it over with pretty frequently and if I slip into another proper depression again I don't think I'll survive it quite honestly.