Why the best science fiction films underuse their special effects budget on purpose

Several of the science fiction films I rewatch most were made on budgets that forced genuine restraint, and I've come to believe that restraint is doing more work than the effects ever could. A film that shows you everything leaves nothing for your own imagination to build, and imagination tends to build something scarier or stranger than any effects team can render.

The films that hold up decades later tend to show just enough to establish a rule, then let suggestion and sound design do the rest of the work the budget couldn't afford anyway. The ones that show everything, constantly, tend to date the fastest, because effects technology keeps improving and yesterday's spectacle becomes tomorrow's slightly dated footage.

I don't think this is really about budget at all, even though budget is often what forces it. I think restraint was always the better artistic choice, and having enough money to avoid it removes a constraint that was quietly making films better.

Related reading: The Guide to Watching Movies and TV More Critically (Without Ruining the Fun) and The psychological thriller adaptation that finally got the unreliable narrator right.