Both Mac OS and Windows started with a mostly single-app interaction model. Switching between applications was slow and clumsy so it wasn’t something that you d

Both Mac OS and Windows started with a mostly single-app interaction model. Switching between applications was slow and clumsy so it wasn’t something that you did frequently. Within an app, copy and paste with styling makes sense as you are trying to reproduce chunks of text. Easy multi-tasking only came later after default were established.