Balanced cables

Just last year I bought a $3,100 XLR cable.
Seven meter Kimber KS1116

For that money you could get a preamp with high output (around 18 volts vs the regular 2 volts). A better higher output component will be unaffected by either the type of XLR cable and/or length. Usually it is interconnect capacitance that affects weak low cost consumer (low-fi) gear resulting in less dynamics. RCA is terrible but of course no serious audiophile would ever use RCA. 

Again it is sad to see folks misplacing blame on interconnects when it is the components that are at fault for any audible degradation.

@elizabeth, again.
Given the posts by Almarg and Atmasphere, do you consider your equipment to be fully balanced?
B

true balanced mainly seem to belong to the marketing gimmicks...

@elizabeth ,
I disagree. From what Ralph/atmasphere has written, it is clear that a true balanced circuit-while not saying it sounds better, provides the means to transfer a signal with far less chance of being affected by noise or being affected by cable design.
I think this is why you are hearing differences between different cables. 

spending twice as much to build the same end result might be OK.

But, you ended up spending a lot of money buying cables.

And I see nothing which would make such designs a requirement for
better sound.

Again, I disagree. Designs like fully balanced, zero feedback and OTL, definitely do make a positive difference.
Though I have no doubt that you have an excellent stereo system, and a sensitive ear, I only wish we could compare our two systems. I think it would be enlightening for both of us.
Bob