2003 was a long time ago: C++ has evolved, Java has stagnated and is falling out of fashion, and many traditional Qt peculiarities like nonstandard strings and collections or the custom preprocessor have gradually transitioned from idiosyncratic but justified to unreasonably antiquated and possibly unacceptable. I think making Qt as "Boosty" as possible is necessary for it to remain relevant.
Might be failing out of fashion, yet Microsoft just bought a Java company, is now an OpenJDK contributor and is one of tier 1 languages at Azure and Amazon SDKs.
Meanwhile, C++ lost its full stack status, the only mainstream OS that still offers C++ GUI tooling, is Windows, and none of MFC, ATL or UWP/WinUI APIs are "Boosty".
What keeps Qt relevant as the surviving C++ GUI framework not stuck in 90's tooling idioms are the paying customers, and those have quite clear ideas which compilers and ISO C++ versions they want to have Qt on.
