From the old policy-holder’s viewpoint, he is getting a great deal. Since he cannot afford to keep making payments to keep his policy going, in his mind the value of the policy has dropped to zero. And here someone comes along and offers him $500,000 hard cash for it!
In this situation there is a loser, and a big loser too. It is the old man’s kids. Had he kept the policy alive, his kids would have been big winners at his death - just like the buyers of the policy will be, and even more so since unlike the investors the kids will not have to pay income tax when the policy pays off.