Maybe you have and just don't know it, because they keep their mouth shut about it and don't flaunt their wealth.
I've pretty much been in the 40 hour work week routine from age 31 until now, age 49, and hit the $1M mark when I was 45. However, before that I worked two and sometimes three jobs to make ends meet. I was hired full time shortly before I turned 24, but kept a part time job I had working at a department store. When I was 26 I was going through a bad divorce, and picked up a third job delivering pizzas, which eventually replaced the retail job.
I got all the debt from the divorce paid off when I was 28, but kept the pizza job. Originally I wanted to keep it as long as I could, so I could sock away the extra money, but as time went by I kind of outgrew the job, and the money wasn't enough to offset the time and aggravation, so I quit at 31.
Now, I had a few other circumstances that helped me along the way. When I was 33, I moved into a second home that my grandmother owned, and she put me on the title as a part owner. I sold my condo at a pretty nice profit. I also took out an HELOC on the house, and invested a lot of that money. However, at the same time, I also built a 4 car garage, did some major HVAC renovations on the house, and put some serious money into restoring an antique car...all things I would not have spent money on if I hadn't gotten that "free" house.
Also, when the market tanked during the Great Recession, I put in some money while the market was down, and that helped me rebound better. also rented a room to a guy from 2004-2015, and that helped financially, although it was annoying from time to time. I rented another room, from 2008-2010. And, to this day, I still have one housemate, who buys most of the groceries, helps out with utilities, and other expenses.
Now, I'll admit, when my Dad passed away in 2017, I got a pretty big inheritance, and that really helped push me up. But, by that point, I was already a millionaire.