I agree with this sentiment, especially when it comes to the important warnings of dystopian fiction (the examples you list, for instance). We always need dystopian fiction as it causes governments to say "Hang on a minute..." When politicians calls something "Orwellian" to prevent dodgy legislation is a good example.

I actually wrote about this subject here, if you're interested (whilst promoting my recent dystopian fiction anthology): https://medium.com/@simondillon/love-and-other-punishments-and-the-importance-of-dystopian-fiction-bfa5d818dadf