I was taught that too, but the deck is stacked. You can still rise, but the odds have been fudged. Big winners, but less of them.
Money/wealth has gravity, the more you have, the more you can pull. Laws that kept money "moving", improving sovcal mobility and opportunity are gone, replaced with ones increasing that gravity.
It is really easy to fall from the middle, to lose,... but if you are at the top you can basically fall up. If you are at the bottom, talent and hard work will get you as far as a lottery ticket... for every one that claws up out of poverty, two in the middle fall and 1000 from the bottom with the same work ethic never get ahead... maybe 1 out of 10 million has the stars align and joins the top, but that estimate is probably high.