I believe Falcon 9 could be priced a good amount lower and still be profitable on a per unit basis (ignoring ongoing R&D) but SpaceX has little pressure to do so as there isn't a competitor with a similar offering. It's interesting, as once Starship is out it may somewhat cannibalize the Falcon 9 marketshare.
You raise a good point about the shuttle, however SpaceX can learn from that. I'd bet they are striving hard to make Starship more effectively and efficiently reusable than the Space Shuttle was. We shall see how successful they are with that. I'd be very surprised if it was not a significant improvement over the reusability of the shuttle.
Perhaps the real paradigm shift will occur once there are two or more companies with fully reusable rockets such that there is more competitive pressure to cut margins and lower prices.
I’m pretty sure Starship is going to be more economically viable than Space Shuttle ever was, I didn’t mean to compare them directly. And you’re right, $1k/kg to LEO doesn’t sound unattainable even for F9.
With the ride-sharing Starship is totally going to cannibalize Falcon rockets, but I thought that was the point all along? I wouldn’t be so quick to retire F9 though. Even if Starship adoption is smooth, it’ll take years to certify it for crewed flights. And there’s always market for smaller launch systems (Electron seems to be doing well).