Who could imagine Steven Spielberg giving the okay for JAWS or E.T. The Extra Terrestrial to be remade? Much less him giving these films positive feedback after such films were released. To some, it would be like doing a remake of Citizen Kane or It’s A Wonderful Life (which influenced Spielberg and his filmmaking style in spades). On one hand, maybe Spielberg should not be compared to Orson Welles or Frank Capra, but he has built a large fan base over the last few decades in which he established himself an innovator and the premiere filmmaker of the summer blockbuster era (along with George Lucas).
Another factor is the studios holding the rights to the films he has directed, such as Universal (films such as JAWS and E.T.), Sony (Close Encounters of The Third Kind), and Disney-Paramount (the Indiana Jones franchise) have final say over to what happens to these properties whether Spielberg likes it or not. They can select anyone to direct or produce remakes of these films without his approval or consent and pursue any vision of these films they wish. The only exceptions would be those Spielberg directs, produces, or owns outright under his DreamWorks SKG banner.
The idea is a weird and strange one to think about, but it is not out of the realm of possibility, for better or worse. Offhand, no one in their right mind could ever imagine a remake of a Steven Spielberg film being done, but again, the studios would be within their legal rights to do so. Many films have been remade or rebooted that moviegoers never thought possible. And remakes of his films can indeed happen, but the question at the end of the day would be. Are they going to be among the few remakes or reboots that are actually good or will they be among the endless stream of bad material that has resulted from such? Only time will tell, but there is no denying many fans of Steven Spielberg hope such a day never comes to fruition.