If it's not that hard to achieve that level of filmmaking, how come Alien haven't been beat yet? There have been/are plenty of A level directors doing their very best in the horror/sci-fi genre.
Too many wink at the audience for one thing. Alien is a no bullshit movie. That's the problem. Every, but every, film suffers from at least one scene where they wink.
The closest serious attempt at another Alien was Event Horizon.
It suffers from some bad editing, bad acting, and bad direction. It starts out fairly promising, but then loses itself to some very cheesy elements.
It's like how Silence Of The Lambs completely redefined a genre and made most subsequent films dealing with the same themes, look like poor imitations by comparison, including its own sequel and prequels.
That's because they are imitations. Hannibal, it's direct sequel was (ironic time) cannibalizing on Silence by using what was a very insidious and interesting character as a primary focus. Too much of a good thing. Plus the over use of gore and carnage, something the original movie used sparingly.
I would say that "Red Dragon" though a remake, was actually a very successful film. IMHO it does a fairly good job of matching Lambs.
Why haven't anyone made sculptures more impressive than what the renaissance era artists offered, advancing the artform to the next level?
Because large portions of the population can't be bothered with said art form to begin with?
I'm kidding of course. You make a valid point.