A lot more 6502 code was self modifying than necessary - I know a lot of people (myself included) did not pick up zero-page indexed indirect/indirect indexed address modes and instead kept using absolute x/y indexed and modified the absolute part for larger loops. A large part of the reason why I didn't learn about it until fairly late was that I mostly saw absolute x/y indexing in the code I looked at to learn. It's interesting how many bad habits you'd see in code like that, given e.g. the C64 ROMs were extensively dissected and documented and published, and they used zero page all over the place.
Raises hand. Yeah, me too.
When I first got zero page, I thought it looked like up to 128 address registers, with only a couple cycle penalty.
But, like you, a lot of code self modified the easier a solute indexed address mode instructions.
And it was right there, easy to see.
I have some 1986-dated 6502 assembly code of mine in hard copy (on dot matrix paper with the "holes" intact). I'm going to scan it one day and post.