There's a massive fee for the basic start up package, which won't pay for itself.
Large, unpopular, out of season or wildly expensive items which are sold to you as an example of 'the full range' of products.
Then you've got to try and find suckers customers to sell to.
If they do buy something, they'll inevitably order something that didn't come with the start up package, so you have to order (and pay for) even more stuff, which delivers a pitiful profit for you, as a large percentage of any profit goes 'upline' to your recruiter.
You are pressured to recruit more 'entrepreneurs' as that is effectively how you profit.
By creating your own 'downline' and becoming their 'upline'.
My local Facebook Selling groups have a lot of MLM remnants being sold as job lots, simply to get them out of the house.
There's a Facebook group called MLM Exposed and they regularly post about new scams, taking the piss out of screenshots of 'mumpreneurs'' Facebook and Instagram posts and former MLM victims post screenshots of the sales brochures and pictures of the events they went to.
One even signed up to an MLM that told the truth (in the small print) - Independent sales people (those who won't recruit and just try to sell products by themselves) won't make a profit.