Yes, you are right; but there are some advantages when you do only few takes!
He filmed Alien that way, and the best reactions are often spontaneous, not rehearsed ones.
Its not only because studios are demanding faster pace that Ridley decided to do lees takes, but
because there are a greater chances to create more real situations in that way. Blame lame actors and
illogical scripts... becuause those two are the main reason Ridley has failed in few of his previous movies,
not because he is doing only few takes. He is not the only great director doing that! His main problems now
are bad choices of scriptwriters and too many ideas in his head that he wants to put in one movie, and the other problem
is the presence of unconvincing actors. Not all of them, but only two are needed to ruin the movie!
P.S. I saw those illustrations long ago, I have all of them on HDD. Amazing work and its a great
shame they did not make to be in the movie. One positive thing is: now there are greater chances we ll see
such scenes in Covenant. Afte rall Prometheus was Ridleys firts SF movie after a long time. I strongly believe
he finaly learned what his mistakes are!