Before &quot;developers, developers, developers&quot; comes &quot;backward compatibility, backward compatibility, backward compatibility&quot;. Windows is perhaps the first commercial platform to commit to Unicode; they made that commitment when UTF-8 was still some notes scribbled on  Brian Kernighan&#x27;s napkin. And all future Win32 implementations must be 100% binary compatible with previous ones. That creates inertia for UTF-16 (or UCS-2), true, but the backwards compatibility guarantees make Windows an absolute joy compared to Linux if you want to write software with a long service lifetime. The decision to stick with 16-bit Unicode is an engineering tradeoff.