That is only part of the equation though. Through this wonderful technology we have access to great and timeless art. We are able to experience it and have more and wonderful choices by the month and year.
I don't disagree.
Access to great art is essential to proper development of the individual and an essential spiritual experience for all humanity.
Again, I don't disagree.
Striving to present great art in finest quality is a laudable goal in and of itself. That is certainly my primary motive in the development and building of fine systems. I regard as part and parcel of the artistic creations being presented.
For some of us there is a point of diminishing returns. Given the situation of many it's simply not logical to pour so much time/effort/money into it. Don't get me wrong, I love to listen to music and watch movies and it pains me greatly to experience it in what I consider sub-par conditions. Some people are content to listen to music and watch movies with the screen and built in speaker on a cell phone. I will never understand how they can bare it.
I don't know the OPs situation so in all fairness I cannot speak to that specifically, I can only relay my personal feelings on the subject. I lack some self control, so that's probably the real problem. I work (not hard) and when I get home the most common outcome is I turn on the television and play a video game, watch programs on Netflix or watch a movie from my personal collection. Often times I'll do more than one of those things back to back and I only stop to get or prepare food and sleep.
You know, as I say that I realize that has little do with the OP, so I'll stop there.
One of my great mentors Peter Walker of Quad felt that way. He was a fine musician and often seen in the flute section when master works were presented at the Three Choirs Festival.
The thing that really drove Peter was to allow his customers to access great art and doing the least damage to it in the process. His manta as you know was "Quad for the closest approach to the original sound." That was his goal and he meant it to his core.
I'd imagine it meant a lot more to him for a host of reasons but mainly because it was his passion and livelihood. Those two factors combined make a compelling argument for him. Someone that would marry him would have to have had accepted that early on. It wasn't just a hobby or past time that served as a distraction for him, it was his life.
-----------------------------------------------------------
To the OP I do think it's worth considering discussing this further with your wife as to what she feels is a more appropriate amount of funds to spend on your home theater / sound system. If we get an inventory of what you already have and how much you have allotted to spend we might be able to come up with a solution that improves your sound system the most of your money and keeping her happy as well.