Have I Hit The Point Of Diminishing Returns?

well sort of .... but not exactly "diminishing returns " but rather a new level of "constant returns".

With a quality kit like you now have, you have reached/ will reach your new upgrade point level. It will now be subservient to that time-honored and inalienable rule that your next "upgraditis" will fall into an inverse trap generally known as the "Rule of fifths"

You have to start shelling out approximately five times the present cost to get the next 20% increase in performance.

That is why this hobby is a journey and not a finite destination.

I've always found Cardas to be very colored try some cables that "get out of the way more". Also, I love the electronics you have. You could always look at changing speakers...Unless you really love those B&W's.I would look at some Dynaudio C1's, or the Contour series. Dynaudios love power! I think you are correct that It will take some $$ to better what you have and its probably not that better. I would add vinyl, this would open a new world and your wallet! LOL.

I totally agree with Mattmiller....tried all the Cardas permutations, and they all don't work in my system....I exchanged my B&W's for Vandersteen and am still smiling after all these years.

No, you have not hit he point of diminishing returns, not even close! There are many, many levels/steps of quality and dozens remain above where you are now.

I am not saying this to belittle your system; you have great gear and I'm sure it is great sounding. However, the steps of improvement are literally endless. In my system also I do not see the finish line, that is, at a level which cannot be improved. Regularly I have dramatic improvements and have for years.

I strongly disagree with the perspective that you must spend multiples more to achieve a 20% change in sound quality. I would nearly reverse it, and suggest that in trying many different components you can achieve a seeming "100% improvement" in not all that much increase in cost, perhaps twice what you would get for the sale of any given component. i.e. sell for $1K, add $2K = $3K new component. And that is potentially at the upside of what you might have to spend. This is because there is a HUGE variance in component quality from manufacturer to manufacturer.

Example: Some of the new DACs are mind-blowing in terms of improvement of digital quality sound, and you can have these for nowhere near nosebleed prices. The new DSD capable DACs are "affordable" as considered to be truly High End, where some components are priced by the multiple thousands.

I encourage you to do some shopping/listening and experiment with your rig. My experience is that the "point of diminishing returns" is perceptual, not actual. And, yes, changing cables, for instance, will alter the rigs sound most likely in a profound way.