why does blind pick still exist?

why do we keep it when team builder is five hundred times better? The only thing blind pick does is increase the time it takes to get into a team builder game so much to the point that it isn't worth trying to Q up for it anymore, so im left with blind pick as my only option to ATTEMPT to get some practice in with a champ or just have a relaxed game, but whenever i try this all i find is instalocking people who no matter what anyone says lock down a champ and forcing someone who called a lane in the first place to play somewhere they didn't want, ruining the game for him/her and the rest of the team. So i propose that blind pick gets removed completely and people that want to play norms play team builder so that no one doesn't get what they want and the long ass Q timers for team builder will be reduced because there will be much more people looking for a game.