3-layer architecture separates the application into 3 components which consists of Presentation Layer Business Layer and Data Access Layer. In 3-layer architecture, user interacts with the Presentation layer. 3-layer is a linear architecture.
MVC architecture separates the application into three components which consists of Model, View and Controller. In MVC architecture, user interacts with the controller with the help of view. MVC is a triangle architecture.
MVC does not replace 3-layer architecture. Typically 3-layer and MVC are used together and MVC acts as the Presentation layer.