It does make it all seem pointless doesnt it? I release my own recordings often. I literally check my mixes on my iphone speakers now.Does any of this make any difference considering that now most people listen to music on really cheap headphones or cheap bluetooth speakers.
Back when I was younger, we would spend a few thousand on speakers separate preamps and power amps were common among enthusiasts. A good sound system back in the late 70's early 80's could easily cost well over $5000, with high end equipment several times more.
Cheap wired headphones sound far less crapulant than folks remember if listening to actual 16bit 44.1khz audio. You need to compare to like physical design as a constraint eg. Not comparing over ears against ear buds, etc.