Does Ethereum account abstraction mean you could make subscription services that withdraw from an account instead of requiring an EOA initiate a transaction, say, monthly?

Blockchain developer, scraping and smart contracts.

Yep! Not sure if there are any smart wallet implementations for this specifically, but definitely doable.

This could look something like a wallet contract setting a time-based spending limit for some contract address, and allowing transfers to that contract (up to the spending limit) to bypass the account owner signature verification step