I am not one who goes for the hype. I test our tweaks before buying them. As to my equipment, I have custom built 22 year old amps, pre-amp and phono pre-amp. My speakers are 28 years old. My modified SME IV is 33 years old. My VPI TNT VI is 16 years old. Yet I still purchased a new SUT last year, Zesto Allesso and a new digital cable, SR Atmosphere Euphoria. So, I have a higher end system as an audiophile but am not into changing equipment without a significant improvement.
As to flat frequency speaker response, I think there is a problem with that statement. One needs a neutral speaker to start with. The better and best speakers have off axis results in a room which tend to boost bass and roll off highs. Reviews of high end speakers show this. Speakers are not heard both on axis in pairs but in a central location in a room. I am not explaining this sufficiently accurately but the gist is that listeners receive a sound like the Fletcher-Munson curve and not a truly linear, flat frequency response. "We are not equally sensitive to sounds of all frequencies so perceived loudness of a tone in fact depends on frequency as well as intensity. Two sounds can have the same physical sound pressure levels but if they are of different frequencies, they are often perceived as having different loudness."
Certainly, every listener has a preference and mostly different preferences for the sound they prefer. That's another reason why there are so many choices in audio equipment. Equipment though, should maintain consistent, neutral character unless the designer wants a colored, less faithful to the recording/mastering engineer reproduction. That's the purpose of neutrality.