Here is one of the Gita's most practical instructions. Krishna says: therefore, remember Me at all times — and continue to do your duty. Surrender your mind and intellect to Me, and you will certainly reach Me.
Notice what Krishna does not say. He does not say: abandon your responsibilities and sit in meditation. He says "mam anusmara yudhya cha" — remember Me and fight. A mother cooking in the kitchen quietly hums a devotional song. A farmer tilling the soil repeats God's name under his breath. Devotion and duty walk side by side.
Leaving the world is not required. Living in the world with your heart turned toward God — that is the path Krishna describes.