Goes to show that the best ideas don't always win, especially when they collide with the interests of critical partners. Maybe it took Napster et al. to really break open the status quo.
Blockbuster's plan failed because too many games were shipping on cartridges with custom hardware on the PCB.
In the NES days it was simple data mapper chips that allowed a program to address more than 40kb of ROM by switching between multiple 40kb data banks. On the SNES this went much further, with games including specialized co-processors for things like sprite scaling, digital signal processing, and even hardware accelerated 3D scene rendering.
Making a universal cartridge that can handle all of this is a challenge even today.