Playing the game out is no longer a good strategy
If you're behind, playing it out only makes it worse. Objectives are so important now that the enemy team can gain piles of gold simply by taking objectives. Now I think objective control is very important, but comebacks are almost impossible when the entire game is based around whoever can salvage a strong enough lead to take objectives easily. No longer can you sit back and farm it out, their lead will grow stronger by just them taking turrets.