The fifth Transformers movie is out now in cinemas, and it appears as though the bubble has finally burst of this decade old franchise's box office appeal. Taking an estimated $15.6 million on its first day in the US, The Last Knight is on course for an opening weekend somewhere in the $60-65 million bracket.

To put these many millions of dollars in perspective, two years ago, the fourth entry (Age of Extinction) pulled in $41 million on day one for an opening weekend of $100 million. Much like the Pirates of the Caribbean series, the popularity of Transformers has dwindled domestically, but the international box office continues to grow. Age of Extinction managed $245 million from the US compared the previous instalment (Dark of the Moon) that grossed $352 million back in 2011. The laws of diminishing returns for sequels is not a new phenomenon, but the last five years have seen big studio tentpole releases become less reliant on success in the US.

The Last Knight is being marketed as the final chapter, Michael Bay has promised he's moving on, and Mark Wahlberg has proclaimed this his last Transformers sequel. Be that as it may, we already know that there's a Bumblebee prequel coming next year, and Transformers 6 is due to arrive summer 2019. Perhaps they mean The Last Knight is the final chapter of the Michael Bay era of Transformers, but Mark Wahlberg recently commented that he suspects Bay will be back for round six.

"You know it's one of those things where Michael has built this entire universe right, and he will decide what he wants to do and how he wants to do it. Right now he says he doesn't want to do another film and he says that after every film because they are so difficult to make and he pretty much has to do it single-handedly, even with all the help that he has because all of the movie is in his mind. So he'll decide that and I would be hard pressed to see him walk away and put it in somebody else's control and care. I mean, that's just the Michael that I know, but you never know, sometimes people decide to move on, so we'll see what happens."

While it's far from perfect, Bay's first Transformers film was hugely enjoyable, and ever since then, he has failed to recapture the formula that worked so well the first time around. I hope Bay does move on as Transformers is in need of a creative reboot as I feel we've just seen the same movie five times.