Is the no-login model the future? As application developers what do we lose by not requiring accounts? In most cases, isn't the account the doorway to income?

Is the no-login model the future? As application developers what do we lose by not requiring accounts? In most cases, isn't the account the doorway to income? How many more applications that don't have a revenue model out of the gates (including Twitter, Facebook, etc.) can the VC community support?