Joe Brody said:
. . .I hope you realize that you are arguing out of both sides of your mouth.
Not really. Your parenthetical correction ("the fakeness") isn't accurate. I'm not equating "fake" with "B-movie."
The set won't look obviously fake like an Ed Wood movie or something. It may be plaster but it will be covered with real moss, cobwebs that look totally real, etc--it will look totally acceptable in the movie. We won't be expecting Shia's foot to kick a hole in the rock walls or something.
BUT, going back to Raiders...the temple is the same way. It's passably real, there's nothing that screams "movie set" about it (on film anyway, most sets look kind of fake in person), but, at the same time, it has some kind of B-movie quality to it. It doesn't look fake but there's some kind of excess lavishness, or slightly exaggerated quality to it that keeps it just this side of believability.
The aesthetic "rules" they've adopted for these movies don't require the utmost realism in the sets. There's a thick line between a set looking obviously fake and looking utterly realistic. And in Indy movies, the sets fall somewhere in that gray area. What you're seeing as the "same old crap," I'm saying, it's not going to look as fake as you seem to think, but if it has that intangible B-movie quality just the same, it's intentional and appropriate.