Yes, because they try to strip the binaries as much as possible so that the file size is smaller. If you compile a regular "hello_world.c" with gcc -O3, the size is 8 kb. You can def make a malware that is way smaller that does something simple like change some registry value to some uri.

Average size for malware is ~100kb-200kb btw. This is way smaller than almost any software besides some console games.

Lots of malicious Office macros and Javascript redirects come to mind. Less than 100K (minus the container) in most cases.