Winning a lottery like Mega Millions or Powerball is extremely difficult. These lotteries sell a huge number of tickets, and the chances of winning are very low.
For example, in the case of Mega Millions, the odds of winning are 1 in 302,575,350. This means that even if you buy a number of tickets equivalent to about 1% of the US population, the chances of winning are very low.
However, it can still happen to anyone with luck, so it can be said that everyone has an equal chance of winning.