When I visited the Warner Bros studios, they had a huge pile of paper in a corner, representing all the unsolicited ideas they receive.
They told us they took care to not even read the manuscripts. I don't remember if they return them unopened or destroy them, but otherwise if the ideas from the manuscript end up in one of their productions, they open themselves to legal trouble. It may happen even if it is a coincidence, so they don't want to take any chance.
Yeah, movies are kind of weird like that. If I steal your idea for a novel (but not your words), you can call me out as an asshole but you don’t have any legal recourse, but if the same thing happens with a movie, apparently it is possible to sue and actually win significant damages.
FYI, in many (most?) legal systems, you can sue anyone, for anything. To win the damages, you'll have to convince a judge or jury of said damages (or present a strong enough case to settle out of court).
Thus my saying, “and actually win”