Fans of the 1970s Wonder Woman TV series will remember that Lyle Waggoner originally played Steve Trevor in Season 1, which was set in World War II, and when the show jumped forward to the 1970s in Season 2, Waggoner stayed on as Steve Trevor Jr. Perhaps something similar could happen in the DCEU, and the Steve Trevor Pine is playing this time is either a grandson (it’s possible Steve the First could have fathered a child sometime before the Great War began) or a great-nephew.
Assuming this Wonder Woman 2 information is correct, what could end up happening is that Chris Pine would not be playing the Steve Trevor that we met in Wonder Woman, but one of his descendants.
The Trevor lineage can continue, and it wouldn’t affect the noble decision the original Steve made.