A compromise thesis might be that in cyberpunk media, AI is at never powerful or motivated to fundamentally reform the worldwide crapsack economic system. They don't abolish corporations, although they might take them over.
Of course, if there was a story about an AI taking over the world into a post-scarcity society, it probably wouldn't be filed under "cyberpunk" either...
Abundance/scarcity isn't really about availability, it's more about access. You can have a cyberpunk story in a "post-scarcity" setting in the sense of availability (due to sci-fi tech) but you can't have it without unequal access to those resources.
A: "Why isn't there more AI in cyberpunk media?"
B: "There's a decent amount already, as characters or tools."
A: "But why didn't those authors address its potential to be even bigger?"
B: "Some did, but that makes stories we don't categorize as cyberpunk."
I think as well if you look closer, many cyberpunk worlds imply AI through robots, computers with personality etc.
Which is a shame, as it seems to me that the overwhelming risk of AI is from the latter scenario, and not as a rogue individual entity.
I liked that mental image a lot! (I try to maintain being uncertain whether Deckard was a replicant)