I stumbled across Reverse Engineering Malware 102 today and read in Section 2.1: Information Gathering Results:
Notice that the file size is pretty small, 2.1 MB. Legitimate executables are usually much larger [...]
And that's the state of programming in 2017: 2 MiB executables are considered small and malware authors are the only programmers that have the knowledge and care to produce such small programs.