So, my take is that "musical" has correlation with objective metrics, yet is heavily influenced by specific individual hearing system peculiarities, and specific gear that specific music piece was recorded and produced with.
You are right for the part i underline ...
But a good designed amplifier will be TESTED for optimal results and for specific ears in a dedicated acoustic room designed around the chosen speakers and the specific ears ...
Then a well designed speakers will play everything well and this nevermind the styles of music ...
But in a non dedicated room , with inferior design , we can imagine customers picking different amplifiers for different music styles ... But this reflect a lack in design or a lack in room acoustics or the two at the same time ... If not a bad synergy between each gear pieces and between the speakers and the room ...
And for your observation that we must buy the same gear than the recording studio, it reflect a confusion and the conflating of the recorded spatial acoustic information and timbre parameters with the different vehicles and coding (digital/analog,dac versus vinyl) but acoustics information can be coded but is not a code , it is a perceived qualia ...Then we must instead of buying the same gear pieces as the recording studio created a better room acoustics for ourself then putting ourself in position for the recreation of the original acoustics information (qualia) in our listening room ... And also buying a BACCH filters DSP to beat even any studio gear which work without them ...
Psycho-acoustics rule the gear, not the reverse... And taste must be educated and rules nothing but only marketing, or sleepwalking consumers , not audio design or experience...
Acoustics moves not only the brain but the heart, it is why acoustics as medecine is an art based on sciences as physics and neurophysiology of hearing not only a technology ...
The most important core fact in acoustics is the active human body producing sounds and perceiving them at the same time ....It is speech/music with his social motivation (meanings) .... We were trained by evolution forces to perceive meaningful natural sounds but more than that we created ourself meaningful sounds ...Our hearing system live then in his own time dimension and cannot be described and explaimed by linear mappings .. Meaning is a non linear symbolic form, it is an embodied form...... I will stop philosophy here ... 😊
«Men are walking idea born from real women»-- Anonymus midwife 👩⚕️