Hard work, luck, and being a bit smart. If you are a smart person who knows what he should do, work super hard and also after you worked hard, you get a bit of luck that goes your way too? Then you are going to be rich.
I have seen insanely smart people, who are lazy and fail, I have seen people who work hard but not smart enough to run a business, I have seen people who are super smart and worked hard, but then fires broke out in California (where he was) and all of his business was gone (thankfully insurance covered most) so there can't be really any of these missing. You need brains, grind, luck and without even one of them you are going to end up with plenty of trouble. So we need to make sure we do our part, which is hard work and brains, then luck is out of our reach.
You've put it the right way, and I actually agree with you with just an addition, but I think it's also covered in what you just said. I believe wealth comes with success, and success can only be achieved if the right opportunities are not wasted and acted upon at the right time. If you are smart and hard working, you will surely get opportunities that might change your life, but you should be smart enough to understand the potential behind those opportunities and use them in the right way because working hard but not on the right things is useless.
Some will say education is the most important thing for someone to become wealthy and successful but I don't agree because there are countless people who are running companies and businesses and are millionaires without even holding an official academic degree. So education might be important, but it's not the most important thing, the most important thing is to act upon opportunities at the right time, and making the right decisions at the right time.