Nolan is a really smart guy when it comes to marketing and budget and understanding the grander picture of what makes audiences want to go to the movies. I look back to something like Dunkirk. Now I have no doubt Harry Styles earned his part, and judging from the movie he did a good job, but I can’t be convinced that the studio heads didn’t heavily advocate that Nolan cast him. And the potential for an entirely untapped demographic to see the movie that otherwise wouldn’t, would be dumb to pass up. Especially with the type of movie it ended up becoming. It’s pretty much an experimental blockbuster. Nolan doesn’t just want to make one massive original innovative blockbuster. He wants to KEEP making them. And he understands, how much more difficult it would be to finance movies of this scale if even ONE tanks or or even underperforms.(He would have to sacrifice creative license, which we all know he wouldn’t do) He talks about it a lot, the privileged position he’s in that other filmmakers can’t do.
All that to say, I think that the whole inception connection, might be a marketing leverage to get more butts in seats, because of the type of movie this could end up being. Now, I don’t think they would deliberately lie, but this could be connected to inception the same way Edgar Wright’s Cornetto trilogy, Sergio Leone’s Man with no name trilogy, or Scorsese with Mean Streets, Goodfellas, Casino were all “connected.” A spiritual sequel of sorts. Now Nolan could make it set in the same world, but the could absolutely stand on its own. Inception is wildly popular, and with the 10th anniversary coming, it would be a smart marketing idea.