I get to look at hundreds of programs. Most I cast aside within a few minutes of looking at them. There are certain program structures that just won't work for most people. Programs which require members to make monthly payments tend to be losers for most participants. Most members pay for a few months, then drop out.
Most programs requiring small one-time payments tend to be a waste of time.
Most, if not all, free downline-building programs are a waste of time. Almost always, the money-making programs that they select to sponsor are ones that I reject out of hand. By taking out referral bonuses. It's easier to recruit people for some programs than for others. On examining the dynamics of a program, you can often make a reasonably accurate evaluation of the probability that a program will or won't work.