I'm guessing if you asked the incoming GM / coach whether they would prefer to have a few spots lower in the draft or an existing team full of players who have to be brought out of a losing culture that was made even worse by throwing half a season they would take the lower pick every time.
Throwing seasons for draft picks happens in video games and movies. There are so many reasons it's a bad idea in real life.
The primary one being these guys don't play in a vacuum. They're being evaluated.
Heard a couple of former players asked about the idea of tanking a season recently. They found the whole idea ridiculous. They pointed out that both players and coaches are trying to save their jobs for the following season. And the idea that a whole team and owner would be "in on it" is laughable especially given that some guys know they won't be here next season.
Bottom Line: It doesn't happen. Nor should it.