In this context, the nearly yearlong success of Ryan Coogler’s “Sinners,” a vampire-themed segregation-era movie, seems even more extraordinary. Arriving last April, it was an immediate box-office hit — its $48 million opening-weekend in domestic sales made it the biggest debut for an original film in six years — and a critical darling. Nine months later, it set a record with a historic 16 Oscar nominations, including one for best picture.