I had a conversation with SAP folks recently and brought up the future of C4C. My current impression in dealing with SAP Support is that it's "maintenance only" and their logic regarding bugs seems to be: SAP standard always "works as designed", so if the reported behaviour is part of SAP it - naturally - can't be a bug. I also noted that there are hardly any new features in C4C, all attention is on v2. In short, my feeling was that C4C is rapidly nearing "last one out, turn off the lights", with SAP probably waiting until all the S/4 transitions are over and customers have capacity to focus on the next migration.
However, the SAP folks mentioned that C4C v1 is still available for purchase and they still have new implementations with hundreds of users. They also said that they're still looking at the "idea place" and at least wouldn't rule out that modern features like AI support would make their way into C4C v1 as well.
They didn't go into any details or time lines, and I'm still skeptical that SAP is going to invest huge amounts into v1. Most likely, they will focus their energy on C4C v2, but if there's a feature that can be easily ported to v1 as well (like AI integration), then they would do it. But I doubt they'll invest massive amounts of money just to bring AI to C4C - unless, of course, they see customers cancelling their v1 subscriptions for this very reason but transitioning to Salesforce rather than v2.
My gut feeling: We may still see some new easy-to-implement features in C4C v1. And it may not be before 2030 after all that SAP announces the v1 end-of-life.