Well I think the WalMart effect was even bigger in the past than it could be now.
Just think about one question:
How many space science fiction Tv shows are around that feel absolutely different than Star Trek?
Star Trek not only influenced, but formed the standards for space Science Fiction with Faster-Than-Light possibilities.
And if tyrants take me, And throw me in prison, My thoughts will burst free, Like blossoms in season.
Foundations will crumble, The structure will tumble, And free men will cry:
Thoughts are free!