Only if you ignore the fact that he was barely in half the movie, that there were three different new characters clearly more important than him to the story and that he was only one of three returning characters who were all marketed together as a group in a 'return of the originals' kind of deal.
Not to mention, Star Wars is in an easy position to pass the torch to a younger generation. It's all about that universe as a whole, not any one particular character. Indiana Jones is more complicated, which is exactly why you're suggesting that it has to be young Indiana Jones himself, and not some new character that might share his name.
And I get why you would think that, but at the same time, imo, trying to throw in flashbacks as a way to jumpstart a new Indy franchise would probably be more dangerous than just doing a straight reboot. Yeah, sure, putting Ford on the poster will get it more attention, but the name Indiana Jones would get people's attention anyway. Meanwhile, if a contrived flashback story fails to gel properly because the new Indy doesn't get enough time for the audience to get to know him, or even worse, if the flashbacks weigh the movie down and get in the way of Harrison Ford's last hurrah as the character he originated, the entire strategy would backfire hugely.
You're talking about a 'passing the torch' movie in which the characters who are supposed to be passing the torch can't ever even share a scene together, can't work together on one story/problem, and basically have to be constantly balanced against each other while trying to create a single coherent storyline that spans an entire lifetime and both wraps up Harrison Ford's time in a satisfying way and sets up 'new' adventures for the new Indy in his past. That's a recipe for disaster.
If they think they can find someone who will be believable as a new version of Indiana Jones himself, then they honestly would be better off just letting him be Indiana Jones, with no involvement from Ford whatsoever. Cast the right person and tell a good story, and it will be perfectly fine.