I don't think it is only (or even mostly) not wanting to accept it, I think it is at least equal measure just plain skepticism. We've seen all sorts of wild statements about how much something is going to revolutionize X and then turns out to be nothing. Most people disbelieve these sorts of claims until they see real evidence for themselves... and that is a good default position.
hedging the possibility that they get displaced economically before it happens is always prudent.
If the future didnt turn out to be revolutionary, you now have done some "unnecessary" work at worst, but might've acquired some skills or value at least. In the case of most well off programmers, i suspect buying assets/investments which can afford them at least a reasonable lifestyle is likely too.
So the default position of being stationary, and assuming the world continues the way it has been, is not such a good idea. One should always assume the worst possible outcome, and plan for that.