It used to be that Outlet stores were was set up to allow for a manufacturer to sell overstock and out of “season” goods direct to consumer. They always sold cheaper but you typically had to drive a good distance to get the deal. Wholesalers and retailer can’t like this it was just a small part as the inconvenience of distance kept it small. They put up with it!
Now online makes it easier to get direct to the consumer. The only trade off for inconvenience is you have to wait a few day (weeks too often) to get your goods but it’s still a lot easier then getting in the car and driving an hour or two.
The outlet malls must be feeling the hit from this. Staff cutbacks will hurt local people, although the companies probably don’t care as they are still making the sale. So will we see a decline in the amount of factory outlet malls? When?