We tend to spend way too much money on cables but for various reasons.
My opinion is that I do not want my main system to perform even a small percentage under its weight so I have bought "real cables " for that. But did not spend fortunes either. My main system cables are worth about 6 or 7k on a total cost of the system of about 100k so they are still at a reasonable level.
With very transparent and high end gear, cables effects can be heard very clearly. You do not have necessarily to spend fortunes. The only point is to be very happy with the final sound. But you cannot buy any piece of metal wire and get rid of the problem.
On my very little system : BiFrost Dac, Squeeze Box, Shindo Apetite and Klipsch Heresy III, the effects of changing cables is really huge, especially for the digital coax cable between the SB and the Dac. You just cannot ignore them.
In this system I used the cables to finely tune the sound to my tastes, like with an equaliser : I lowered and sweetened the treble response by using a carbon made Van den Hul " The First " analog IC.
I get almost zero effect with the power cables. JC VERDIER told me that in France, the power is very clean in most cases and people spend fortunes in power cables and power conditioning / filtering for very very little effects.
I miss the old times of HiFi. My MC2205 really does not care which cables I use with it, IC or speakers : it always sound musical and delicious. I guess that gear was made with a different approach than the extreme transparency of most today's gear....