gfoot on Tue 15 Feb 2022 wrote:
It seems odd to me that it would be economical to use a cut-down CPU and supplement it with custom banking logic
This inefficiency is deliberate. Many game consoles have been sold at a loss. The profit comes from selling games but people don't buy games unless they have a console. If the console is slightly cheaper than more people buy consoles and more games are sold. This is a false economy for a customer. However, the majority of game purchases occur after the console is a sunk cost.
Actually, I presume that all of the Atari 2600 game consoles were soldered manually. Soldering 28 pin 6507 rather than 40 pin 6502 would save considerable effort. It would also reduce production line theft because 6507 is less useful with 13 address lines and no NMI.