The short answer is no. Amway the company is not a scam. However, IBOs powered by Amway and/or leaders from groups connected to Amway such as WWDB, BWW, or Network 21 can end up scamming people by using the Amway opportunity as a front. They'll promote Amway as a way to earn a lifetyle of the rich and famous. They may promote Amway as a means to earn lifelong financial security. The catch will always be that you need to follow their system.
The system normally consists of cds, voicemail, standing orders, books, functions and seminars. Some of this technology is outdated, but likely has not changed in many years because uplines profit from the sale of these "tools". It's basically a bait and switch. They lure you in with the hopes and dreams of a fabulous life and uncoutable cash rolling in. They then sell you the secrets of gaining these trappings. Sadly, only a tiny fraction of 1% will ever see any kind of significant success. And out of those who do enjoy some significant success, many of these people find out that Amway success may not be sustainable.
The truly horrifying result of all this is that probably 99% or more people who have dreams of a better life and financial security will actually end up with a net loss of money and time that they could have used more productively. In my IBO days, I saw some crossline lose their homes or enter bankruptcy following the advice of their trusted upline mentors. It almost always had something to do with skipping out on financial obligations in order to buy more tools or to attend a major function. The secrets of a diamond lifestyle is apparently to sell standing orders, functions, voicemail, not not necessarily selling Amway.
If you look at the arnings of platinums and diamonds, you will easily see that thos kinds of incomes cannot sustain million dollar lifestyles, especially when you factor in business expense such as traveling and hotel stays. If diamonds fly first class everywhere they go, that's a lot of cash to run their businesses.
So is Amway a scam? No, Amway the company is not a scam, but Amway IBOs and Amway IBO leaders who run functions can certainly scam you. Beware!