[nl]

Some affiliate programs are loss-leaders.

They assume a proportion of the buyers will be repeat purchasers. Paying for a loss-leader product for 100k casual visitors with unknown demographics or purchase patters is riskier than many businesses are comfortable with (for good reason!).

Also, if you are Fred's custom napkin business, and you usually sell 10 napkins a week and suddenly you receive 100k orders you are going to have a problem scaling a physical business that quickly.