I have to agree. Movies just don't seem as good anymore and risks just aren't taken. The last film I can think of that seemed risky, off the top of my head, was probably The Matrix, and iirc that was a 1999 release.
For me, it probably began to change when movies went from 'a thing to entertain that hopefully also makes a sh*t-ton of cash' to 'a thing to make a sh*t-ton of cash that hopefully also entertains'. It's hard to imagine Blade Runner getting made today. Sure, there's the sequel in the pipeline, but if it wasn't a sequel...?
Obviously each film costs money and the studios want to make more back than they lay out - it's unsustainable any other way. It's just that, in the past, execs seemed more willing to take a chance. They still had stats and financial figures at hand - SK, in Danse Macabre, mentions that in the late 70s the studios had clear audience demographics and so on (and unsurprisingly, the 'core' audience then was what it is now, people in their late teens and early twenties) - but someone, at some point, would look at a script or an idea and give it the green light. (According to several DVD extras and programmes on the subject, one of the biggest risk-takers was Alan Ladd, Jr.)
The (over-)use of CGI has to be considered, too. From Jurassic Park on it's been easy to create spectacle, and to a degree spectacle became the focus of movies rather than story, culminating - arguably - with Avatar. Maybe that's understandable: you had a generation of film-makers who suddenly had the keys to the candy store and all the toys in the toybox, so they went a bit nuts. As the next generation begins to shuffle in, CGI spectacle is a bit old hat - they've grown up with it, it's their normal - so maybe there'll be a move back to story. To an extent, the signs are there.
Against that refocus/reinvention will be the studios. They keep pumping out sequels and prequels and reboots and superhero films (or sequels of reboots of reboots of superhero films, e.g. The Amazing Spiderman 2) or rom-coms because their numbers say that's what audiences want. Of course, the counter-argument to that is, if that's all studios are making it's all people can see, so of course it appears that it's what the audience wants. Then, when someone produces an indie movie or the studios deign to invest in a 'quirky' project and they suddenly take off, we get articles along the lines of 'Success of low-budget/indie/'off-beat' movie [X] takes industry by surprise'.
As I said before, you can understand the studios wanting (or needing) to make money, and plenty of it if possible...but they used to spread it around a little more. For every 'banker' (many of which flopped) there were movies that not much was expected of. Then there were the 'flops' that proved to be anything but in the longer term - again, Blade Runner is a case in point. Not that much was really expected of Alien. Look at that now.
I think the studios have tried to turn the numbers game into a science when it really isn't, and TV has taken the risks that film used to. Video games, too. Given the choice between re-watching Prometheus or playing Alien: Isolation, I know which I prefer. (The story in A:I is stronger than that of Prometheus, and would have made a decent movie in its own right. The One That Got Away, Sir Ridley.)