I think Starlink is for rural customers and can't compete with decent wired broadband. You were the one who seems to be putting it against cable (which exists in the metros, not in rural areas).
The MIT work linked in this thread calculates a total worldwide capacity in the ~20 Tbps range for Starlink.
I didn't see the link, but here's the presentation[0] I believe you're referring to. It estimates Starlink's max total system forward capacity at 23.7 Tbps.
The MIT work linked in this thread calculates a total worldwide capacity in the ~20 Tbps range for Starlink.