Over the past 15 years, I've had the opportunity to work with more than a dozen MLM companies in the UK. This won't be a popular opinion, however I believe great quality products and a self-regulating industry can create businesses that are far from being a Ponzi scheme but are legitimate companies with ethics, great support and opportunity to earn decent money.
None of the UK-active MLM schemes I've seen has an ethical reason for using MLM rather than legitimate sales channels.
Let's look at some. Cleaning products that are vastly more expensive (in part to fund the MLM commissions) than High Street equivalents. Questionable dietary supplements that rely on woo-woo rather than scientific backing. And of course, electricity, gas, and phone service with the added margin to pay for all those ad-emblazoned Minis and, again, MLM commissions.
Maybe it's like communism. People like to say that, on paper, it's a great idea (I disagree but that's not the point). Those same people also say that it has never been implemented properly, and so it's not the fault of the idea that it has always led to national scale human misery.
In your view, MLM could lead to ethical companies with great products etc. But the past few decades show that every time it's tried, MLM actually preys on the dreams/needs of the vulnerable, adds huge margins to mostly crap products, and the people who get suckered end up mostly losing money.
MLM is a horrible idea that leads to horrible outcomes.