Re: state-of-the-art silicon (6502 then...)
> cheap enough to play with, and slow enough to work on breadboard
It does seem like a strange comparison.
When even the CPU in a toothbrush is powerful enough to play Doom, the problem doesn't lay in finding cheap hardware to experiment with.
I mean, look at how many products have spawned from the Raspberry Pi and/or Arduino; the former in particular offers a (fairly) cheap general purpose computer which is powerful enough to run a full OS and which can easily be hooked up to physical hardware via the GPIO pins.
If anything (and without wanting to sound like I'm paraphrasing the "640k is enough for anyone" quote), hardware has arguably peaked; while there's still plenty of need for number-crunching supercomputers, there's arguably very few mass-market problems which can only be solved by throwing more powerful computers at them.
Instead, it's all about software these days.