It's not just hard work, it's the right hard work.
I'm not rich, but I'm doing really well. I've got there by putting myself in the way of luck, and yes, working really hard, after getting the right education - which I also worked really hard to get, since my parents are also not wealthy and so could only offer a small amount of (much appreciated) support.
Basically, every big decision in my life was carefully considered - from my A-levels, to not getting a pet until I'd 'made it' so I could move around as much as I needed to to get the the next good job.
I was willing to do things that other people weren't - move country at the drop of a hat, work weird hours (currently in a meeting, I started work at 6am - as I have done for the last 3 years to overlap with another country and so that I can still look after my kids since I'm also a single mum). And I was willing to take risks - some paid off, some didn't.
If I'd done what my siblings had done - taken degrees they were interested in (not that I'm not interested in my degree! But that wasn't the primary driver), taken jobs close to where they liked to live, had children an pets and hobbies that they didn't want to compromise with or delay, then I'd be like them. Middling to OK - which is fine, if that's the life you want. If you want to be rich (and you're not born with money) then it's going to take sacrifice.