Oh, sure, it was obviously limiting the other tasks. The point was that this is almost always the right choice for a general purpose operating system: no user wants to have their music skip, UI go unresponsive, file transfers to fail, etc. because the OS devoted resources to a batch process.

You’re only partially correct about classic macOS: you could definitely hang the OS by holding down the mouse button but this wasn’t a problem for playing music, burning CD-Rs, etc. in normal usage unless you had the cheapest of low-end setups because a small buffer would usually suffice. I worked with a bunch of graphic designers back then and they didn’t get coasters at a significant rate or more than their Windows-using counterparts, and they burned a lot of them since our clients couldn’t get large files over a network connection faster than weeks.