why do people feel the need to buy expensive cable

That’s a bit like trying to prove that classical music is superior to jazz?

Of course, it is superior. Jazz musicians don’t even know where the right notes are constantly searching for them. For instance, Jazz bassist "walks" all over the finger-board to find proper note, while classically trained bassist knows where the note is and just plays it.

Why wonder, listen to them. Go to THECABLECOMPANY.com and access their lending library. Listening is the only way to know. 

also see, JPSLABS.com

A good medium priced Cable is the least you could do pending on your system 

I don't buy expensive cables.  I buy the ones that sound the most incredible (actually, they don't sound like anything at all).  Just so happens that those are...expensive.  Cables tie it all together.  That system should give you goose bumps.  

Taters

I doubt that your system is completely to blame for not hearing enough of an appreciable difference in the way your system and music sounds.

The only way to determine if a cable will make an improvement to your system is to play it in your system. 

Perhaps getting brand recommendations from 'goners based on their positive results will be a useful guide. 

Suggest:

Consider including all categories available such as: power cords, digital power cords (for cd players ) - (JPSLABS for example), interconnect cable, speaker cable, and digital interconnect cable - (between transport and DAC).

See the lending library at THECABLECOMPANY.COM
also,  JPSLABS.COM

Keep trying !