Although anyone may learn the game's rules for free, you must invest time and of course, money to hone your talents before you can start winning seriously large sums of money. There wasn't much competition back then, therefore hitting large sums didn't require so much work.
The game has evolved over time and there are many reliable sources available. I recall how challenging it was to locate reputable training programs in the past. Books were pretty much the sole source. Nowadays you have some really good courses like Raise your Edge, Upswing poker, Pokernerve, Run it Once.. .
And dont forget Cardschats 30 Day free course.