Comment by com2kid

People forget that prior to Microsoft releasing Defender, antivirus on Windows was universally bad. Like "make your machine almost unusable" bad.

This was also before SSDs as well.

With local build times already measured in multiple hours (large C++ code bases, lots of caches obj files loaded from central build servers to make local incremental rebuilds even possible), Microsoft didn't want to make things worse by forcing any bloat on developer machines.