It's really depressing that we've come to this spot, because economics kind of inherently favor tried and true branding over original ideas, and it seems like there's no going back (especially with the currently enormous international movie market). It's like we've just been really lucky that the studios didn't really figure this out and embrace it until the 80s/90s, which is why you could have the top 5 grossing movies in almost every year of the 70s/80s be an original feeling movie. Now, what's interesting to me is that this doesn't necessarily mean the movies have to be original properties.
Look at 1982: We got E.T, Blade Runner, Road Warrior, Conan, The Thing, and Blade Runner coming out within weeks of each-other. Now these mostly aren't original properties, Blade Runner/Conan are book adaptations, Road Warrior is a sequel and The Thing is a remake, but I would argue that the movies themselves feel very original for their time, and have very distinct identities that have made them live on over the years.
Maybe the bigger issue than even the branding is just how goddamn similar every movie coming out feels these days, regardless of what it's originally based on. Slowly but surely, it feels like all personality or quirkiness has been leeched out of genre film-making, and worse still, audiences have become conditioned towards this to the point that they will tend to reject a movie that doesn't follow this template. Trey's comment about sky-scrapers falling down in every movie is very on-point, and I would argue the same thing has happened to creature design. When is the last time we've had a cool iconic movie creature? Attack the Block is the only really recent example I can think of, and that's a pretty tiny movie that made very little money at the box-office.
This is why District 9 and Children of Men were such a breath of fresh air when they came out, because they had a very unique tone, identity, and approach that does not follow the typical blockbuster mold.