+ YouTube + Amazon: Lets kids see what a toy looks like in HD, whereas previously you'd need to go to a store to see the big images on the box, or to press the "try me" buttons. As you said, the brand drives most of the sales, so the store experience adds little.
+ Advanced Supply Chains/McDonalds: The toys in Happy Meals are insanely nice, I wouldn't be surprised to see them retail for $5-10 at a toy store. High-quality toys are throw-ins for a lot of stores now, obviating the need for a special purpose store, save for Christmas/Birthdays.
+ YouTube + Grocery Store: The rise of Surprise Eggs over the last few years has been astounding, to the point that a decent amount of our toy budget is spent at the checkout line at the grocer, where these eggs are increasingly on offer.
+ YouTube + DIY: The explosion in popularity of DIY slime is another development where tactile time is invested in a project rather than a packaged toy.
+ Apps: The YouTube Kids app and the many thousands of quality games on offer in the app store are great substitutes for plastic junk.
No doubt debt played a role, but I think almost every story has underplayed massive changes in the toy market that are an additional headwind to the industry.