Ironically, it was the retail chains themselves, especially the carnivorous GameStop, that helped make online stores such a success. I'll never forget a decade ago when their management decided that PC sales simply weren't worth it, moved the PC titles to the back of their stores, and instructed clerks to tell people they could only order PC games for them if they'd first stocked them. It didn't help that at least some clerks (if the experiences of my wife and myself were at all typical) thought it their sworn duty to belittle PCs and PC games in general even as people sought to buy them.
Which of course meant that all those PC users, who also accessed the Web, were available as a new market. And from there, it was pretty much a small step to harnessing the same techniques chosen to make site PC sales more attractive--gameplay and trailer videos, special deals, beta programs, etc--for the consoles.
The economic model for game sales on the Web clearly works. I only wish I could ask the GameStop people who decided PC users should abandon games if they'd thought about converting their stores into arcades, or possibly ice sculptures.