Go's creator still uses and promotes Go. Python's creator still uses Python. C++'s creator still uses and promotes C++. Java's creator still uses and promotes Java. But Swift's creator no longer uses Swift AFAICT.
Did he ever use it much? It’s not self-hosting yet, so he’d be more a user of C++ than he was of Swift.
He is developing Mojo now, so i guess he has no reason to use it now. Also perhaps developing a new language is an admission that the S4TF was a failed effort.