I completely feel this post.
I started out on a council estate. But my Dad started doing quite well and so got a mortgage on the family home. By age 10 my parents separated and that's when my mother had to get a job that paid more than a little bit of pocket money. But she was never career minded or motivated and soon met someone else who covered all her major costs (mortgage, bills, multiple holidays abroad every year just for them 2, major car expenses, clothes etc). My Dad ended up with a really good job, moved overseas, and has since lived a life that's completely chalk and cheese to how my life started. So I've been exposed to 2 very different lifestyles and attitudes.
My Dad didn't go to Uni but did go to grammar school and that gave him a step up in life for sure. He was very hard working but definitely had a sprinkling of luck thrown into the mix. Some of his great lifestyle is also down to sheer bloody-mindedness. I lived with him for a couple of years as a teen, but he virtually abandoned his family (incl me) after moving. If he'd been around and/or given any financial support, he wouldn't necessarily have the wealth he has.
My mother, in contrast, isn't very smart or savvy, and was happy playing more of a housewife role (though she wasn't a very good mother). She not only did well through the divorce, but also ended up with someone who paid for everything for her. She now lives with him in a modest house but in a lovely location in an affluent area and they both have nice cars and a very good quality of life.
In further contrast, I went to Uni in London and from that point stayed away from home, looked after myself financially and every other which way because my Dad wasn't around and my mother didn't want me around, didn't have kids because I feared not having enough to give them, and worked bloody hard. Things were on the up until I was unwell and had to have surgery, and after that felt life was too short to work hard forever, so spent 4 years overseas barely surviving in poorly paid jobs, came back to the UK, struggled to get into a new career, several years later things finally improved and now I'm in an ok paid job but definitely earning a lot less than I should be, and I have a mortgage on a house that's probably a tad smaller than the council house I started out in. I have an old car. However, some of this is lifestyle choice as I love to travel and spend several thousand each year on big trips. Given I don't have kids though, and given where my parents are in life, it does feel like a kick in the teeth.
By comparison, nearly every friend I've ever had has had a very different set of circumstances. And that has been due to family support (financially, emotionally etc), and family and/or friends aiding with employment opportunities. In most instances, I'd say they didn't work as hard or any harder than I.
And my sister, the (first born) golden child, didn't go to Uni, did study for a professional qualification whilst she worked, but could afford a mortgage very early on in her career on 12k, was loaned some of the deposit by my mother, and always had men dropping at her feet, which I'm convinced enabled her to go further than me up the ladder. Though even she hit a ceiling and wasn't really that senior (but was the main earner), but she has somehow managed to retire at 51, with a really lovely family home, nice cars, a teen son, has always taken several expensive family hols per year, goes out every weekend and does things you pay for including concerts and theatre etc, dines out at least every weekend, and doesn't want for anything. She even travelled the world for about 18 months when she was in her early 20s and I've never understood how she managed it to be honest. She says she's made her luck, but I was always the more studious with the better grades. So I simply don't agree. And she had the audacity of once telling me I couldn't have everything in life when I said to her I'd at least like to have a small house and the ability to go on a nice holiday once a year.
So in my minds eye, life is a lottery to be honest. You can be reasonably well educated and the hardest working but not the most attractive, and end up with not much more than (or even less than) someone without an education who lives in a council funded house but has spent 20+ years working their way up from a junior role to a reasonably well paid job. Or you can simply be attractive, have no interest whatsoever in education or working hard on anything other than your aesthetics and live the life of luxury.
In this day and age, if I had kids, I'd have them.living at home and would advise them to do an apprenticeship as it teaches them skills whilst giving them pocket money. I now work with individuals younger than me who had this privilege and they're nowhere near as hard working and they get away with it, yet they earn more than me.
I try to just be thankful for what I have, but I'm not gonna lie, it's impossible not to feel resentment at times.