People drink less office/gas station coffee than they used to, and so can drink more Starbucks/independent coffee. The same didn't happen to the mom and pop video rental places (though the ones that survived blockbuster, usually by being in a market too small to support a Blockbuster, often outlived them (the one near me closed a few years ago finally)).
I didn’t play games much but I recall them also renting out Japanese nintendo games and also sold the necessary cartridge converters to play Starfox.
The "name" of the reason might be Blockbuster, but the actual reason was that Blockbuster had a larger selection. Those mom and pop stores were really small, so if you wanted something else you had to go to Blockbuster anyway, so why bother dealing with more than one store even for the stuff they had? Just get everything at Blockbuster.
It's the same with retail stores - I don't go to the small stores, even if they might have what I want - why should I? I can go to the larger store and get everything and not have to think about it.
In another town we lived in, the video rental place was a local chain with fewer than 10 locations, maybe just around 5. I don't remember if a Blockbuster even existed locally.
essentially blockbuster operated at larger scales than many small video businesses and so had smaller unit costs while also having more selection.
Is there a source for this? Usually, both rise and fall together with consumer demand. When I grew up, Blockbuster was one of a dozen options in town.
As an example, there are more independent coffee shops today than before Starbucks expanded.