The Shelby GT350 only just scraped into the '15 model year with 137 examples to match the 137 from 1965.
If S650 launches for a '23MY, I think it'll be at least the '24MY before we see a new Shelby........at least a Ford Performance Shelby.
Shelby American on the other hand.........as the Shelby GT is mostly a cosmetic package, the boys from Las Vegas could have their version available sooner.