I know there's already been speculation on this but what I haven't seen anyone notice is that this film hasn't been marketed as the ''final'' Indiana Jones movie (simply as the ''4th). You'd think if it was going to be the final movie that it would be marketed as such, something like "The Last Chance to See Everyone's Favorite Archaeologist" or something.
I also don't recall Spielberg or Lucas ever saying it was the final movie either. And given that recently Ford said he'd do a fifth Indy in a "New York Minute" so long it as it doesn't take 20 years, I can see it happening. If Harrison can pull off Indy at age 65, why not at age 67or 68? Wasn't John Wayne still starring in action flicks well into his 70s? So was Connery (League of Extroadinary Gentlemen). With today's technology, it certainly is possible. It's not like he'd really be physically going off on an adventure, it's a movie.
Especially if it each movie was set with KoTCS set in '57, the next movie set in '58 and the last maybe set in '59 (if they went so far as a new trilogy) that would keep the series in the realm of the '50s and not expand it in the '60s (which I don't think would fit with IJ), Indy's age would still be reasonable, he'd hit the 60 mark in the last movie and call it quits.
Shia's role--if he is good and proves popular--could expand in the 2nd and 3rd movies and maybe from then on he could take the series into the '60s as the lead. But it would be a slow transition over the 3 movies. That's thinking into the future, but it'd be awesome to have at least one more Indy after this one, especially if this turns out to be good. And if this Mutt character turns out to be interesting, it could be a good way to keep this series alive for generations to come.
