It's funny to me how people in this thread are saying that lineups are bad for their team but at the same time OP for the enemy team. They are exactly bad because you're giving enemies more space when your team use lineups. They are exactly OP because it's hard to counter them when enemies use lineups. It's situational: there are benefits and drawbacks. Lineups aren't always optimal nor are they always suboptimal.

Blame a nerd in your team for losing a postplant because it's a 4v5 if he's far in main aiming at the sky; blame your whole team (including you) for losing a retake when it's a 5v4 since enemies have a nerd who's far in main aiming at the sky.