> Also you're not using the stack to pass parameters to routines here either. You might not even use subroutines.

Well that 128 bytes was in the upper half of page 1 and the 6502's stack was in page 1, but at least one source says that the upper half of page 1 was also mapped to page 0.

I'd guess that at least some programs would push to the stack - if nothing else you could save a byte when storing a byte to memory (PHA vs STA #FF).