"Actually, I’ve been reliably informed that 6502 processors are still being produced by Western Design Center, so clearly 6502 isn’t a dead language! Who knew?"
A lot of the ARM instruction set was based on the 6502, so 6502 assembly language won't completely die even if the chip does. I found that my experience with the 6502 gave me a useful head start when I started ARM programming a few years ago.
Many embedded systems still use them, and they're found in SoC form in various peripherals - my mouse has one, for example.
Other products I've seen 6502 cores used in are digital picture frames, LCD monitors, MP3 players, Tamagotchis, and touchscreen controllers. The 8051 (another odd and old architecture) probably outnumbers it, but the 6502 is still well and alive.
Fantastic! Earlier today, after play TIS-100 for a week, I decided I wanted take a shot at making an Atari 2600 game. Currently reading Assembly In One Step, after that I'll read this.
I didn't. Good news :)