Everyone will be rich definitely if they're for real. If addresses that have balances on it and someone has got their private keys, it won't make sense to sell them. They'd totally sweep it out and take out those balances and leave them alone, it doesn't make sense right?
But is it just a fraud , once you send BTC to it , it just goes to the scammer and nothing will you get.
Those greedy and gullible folks are their targets and thinks that it's easy like that to get private keys with real balances in it.