I own the expensive stuff and I did not feel it was lacking- at least not until I tried some upper tier cables. I don't see it as tuning or tweaking. It is refining. The music is there, the detail and the soundstage is there. Its more like polishing the mirror to get a clearer, sharper picture.
One other thing I'll add that I thought of. Cellos and Bass violins sound like they are there now. Before it was mostly a cello like sound. Now, all the nuances and resonances of the cello are present- even when streaming music. I stood 10 feet in front of a cello player in April and listened closely to all of those nuances. For all I've spent that gives me a lot of satisfaction. I think the lower registers are the toughest sounds to reproduce correctly which requires both room, electronics and cables to all come together. Speakers help a lot too, of course.
Accolades to my wife who has patiently permitted me to round out my system with some nice cables. (She got some benefits from it all too in the form of things she likes.)