Maintaining a "Balanced" System Design?

After recently upgrading my phono stage, amp and preamp to all ARC, I have begun to explore speakers and have plans to listen to some Joseph Audio Perspectives in the coming week. 

However, in the process of talking with the dealer, it was suggested that I should upgrade my interconnects and speaker cabling. He has suggested all Stage III gear, which is almost as expensive as the JA speakers. 

My question is not to necessarily debate speakers or cables, but to instead hear some thoughts about not over-weighting one's system with a component that exceeds the rest of the gear. For instance, I realized that my current turntable/tonearm/cartridge combination deserved more than the $3k phono stage I had been using. So I moved up to an ARC and really noticed the difference. Of course that brought me to looking at amplification and I am sure everyone knows the story from here...

But, how do folks allocate or balance their systems?  I am pretty sure adding $15k of cables is more than makes sense, but maybe not?

Thanks to all who would like to share their philosophy and experiences.