Back in the day if you wanted some, say, swivels, you would have no option other than to visit your local tackle shop and hope that they had your favourite make in stock (and what a nightmare for tackle shop owners; they can't stock every brand or swivel or hook, etc) so you hoped for the best) and while you were in there buying your swivels you then made a load of impulse purchases at the same time.
Now, why drive for half an hour or more to your favourite tackle shop to buy your swivels not knowing if they will have the right brand when you can go online and in less than a minute have them winging their way to your front door?
Less footfall for the tackle shops means less business means less profit. I think anyone that actually wants to own a tackle shop must be clinically inane anyway but the way things are they have no choice