For an extreme example, think Transformers, where hundreds of millions and dollars can't save bad writing. Making things better at the screenplay level is probably much more cost-effective than spending millions in VFX (or, in this case, creating a full language where subtitled not-entirely-random gibberish would probably do)
The box office result says otherwise.
(Note: I'm explicitly making an economical argument, not an artistic one, since that's what the thread focuses on.)
Certainly there are good "little" movies that get made on a relative shoestring. And even more shorts and arthouse fare. And modern video equipment makes it a lot easier to mostly use natural lighting and the like.
That said, mainstream TV and movies have made most of our standards pretty high. I'm always somewhat amazed by how much gear gets brought in by a video crew to shoot a few minutes of talking heads to use on a company web site.
Plus, once you have a language, you can translate an English script into it vs constantly making up (inconsistent) foreign dialogue as you go.