Absolutely not.
If everyone in the world attempted to cast off religion, it would greatly displease the Chaos Gods to such an extent that they may intervene in our plane just to satiate their desires of the human emotion. You see, the Chaos Gods were created with the first humans' emotions, and will cease t exist with human's emotions. Khorne, the God of War, requires religion as the major basis of fighitng worldwide to keep him content and not cause the Rapture, as it may be called by the misled. Regardless of this, Nurgle will ultimately hold sway over the tangible human bodies, as he is the God of Disease and Death. His plans do not matter so much either though, when put in comparison with those of the oldest Chaos God, Tzeentch. Tzeentch's plotting and scheming as the Chaos God of scheming and plotting (among being the changer of ways, and the guider of fate) is for his own personal gain. It is because of Tzeentch that right now our world does not yet worship the Chaos Gods. It is because of Tzeentch that we do not all believe in peace, and it is also because of Tzeentch that you posted this question. Neither you nor I can comprehend the ends or the means of Tzeentch and his plans, but everything that has ever happened, is happening, or will happen, is all part of the grand scheme of Tzeentch's plotting.
This concept is hard to understand, yes, but you will eventually understand that anything is for the doing of Tzeentch and cannot be changed, or Tzeentch would change it.