It's Good Back To The Future 4 Never Happened

screenrant.com:

While there's been plenty of talk over the years about a possible Back to the Future 4, it's actually a blessing that a belated sequel never happened. Director/co-writer Robert Zemeckis and co-producer/co-writer Bob Gale are the gatekeepers of the franchise. They had it written into their contracts for the series that further sequels or a reboot couldn't be made in their lifetimes without their approval. In the intervening 30 years and counting since Back to the Future: Part 3, said approval has not been forthcoming, with the pair making it clear that the story is finished.

In lists of the best movies ever made, Back to the Future is often among the ranks. Its deceptively simple elevator pitch, "what if you could travel back in time to meet your parents when they were your age?" is transformed into a fantastically clever adventure that encapsulates the Amblin spirit of the 1980s. Though its ending tease wasn't originally meant to spawn a sequel, the film’s success resulted in Zemeckis and Gale conceiving a trilogy to tell a bigger story. Back to the Future: Part 2, and Back to the Future: Part 3 were filmed back-to-back, and while they didn’t reach the acclaim of the first movie, were nevertheless successful. Appreciation for the sequels has grown over time, and many have never given up hope on Back to the Future 4.

Related: Every Easter Egg In The Back To The Future Movies

Notwithstanding fan demand, Zemeckis and Gale are correct that a 4th movie would be a mistake. The Back to the Future trilogy forms a complete story with a beginning, a middle, and an end. The finale of Back to the Future: Part 3 wraps up the adventure perfectly, giving Doc Brown a new life with Clara, and Marty having a world of possibilities ahead