why do people feel the need to buy expensive cable

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 !

people feel the need to buy expensive cables because they lack the technical knowledge to distinguish snake oil sales pitches from real engineering

mystics chants of "everything matters" and "skin effect" are helpful to delude these poor people

you might also ask why are some people anti-VAXers

Science is as much a religion as  any other .
The reason people do anything is a search for meaning and hope .

Of course, the difference is you can have mathematical proof and you can prove physical theories. But you cannot have religious proof.