Has Radicalizing the Rig Led to Revolutionized Listening?

I'm with you from both angles, gear and age.  As your gear sounds more natural, it's more enjoyable to listen to natural sounds than synthetic ones, especially with voices.

When I was young, I wanted excitement from life and my music.  Now, I find myself seeking calm more often. 

Follow your tastes. But yeah, I agree with you. Though the physical act necessary to set a guitar string in motion does allow the electric guitar to attain an unmistakable acoustic instrument integrity/veritas/credibility, in the main acoustic instruments simply possess more primal mojo. Acoustic instruments just have more life in them. They better convey artistic expression, i.e., what's inside. And of course it doesn't hurt that an excellent audio system has the wherewithal to deliver a good deal of that life.

I’m 60, and indeed for a few years there as my system-building phase neared completion about 5 years ago, I too shifted more and more toward the acoustic. But, about a year ago, I sorta rediscovered my rock roots all over again (this time with the newly finished dream system). At first just some select titles, then it was almost like a dam broke that I didn’t realize was there. I had worked hard from the start to get a setup that could do any genre equally well (not easy), but it was paying off well.

Maybe going back to my musical beginnings is aging, too?? Can’t say for sure. It was almost like I was unconsciously rebelling against the act of trying to ’think too much’ about the listening experience. But, my (finally) having a rig that doesn’t editorialize at all about whatever material I could ever want to listen to, was the difference-maker to me.

Don’t know where my musical tastes will go next, but I doubt my music genre explorations days are behind me.

It's such a rewarding experience to have a fulfilling listening session every time one sits down before the system. I couldn't relax and simply let the music wash over me when it had major faults as I interpreted them. But, with the elevation of the sound quality, I could relax and sense the reality in it. 

That level of quality is far higher than I dreamed it would be; i.e. the cost to achieve it was far higher than I had imagined. 20 years ago I never thought I would put so much into audio, but I wisely budgeted literally a certain amount each year to expend to build it up. That has paid of handsomely, and if not for that this discovery of the raw beauty of acoustic may not have happened. 

I concur that nostalgia can lead you back to other genres. I find myself listening to performances of 30 or more years ago with glee, as they are so well rendered by a good system. I hear, and appreciate so much more now than when I was young. The artistry is what shines through on such performances, and when it is rendered beautifully it touches the soul. 

Vocals, too have changed for me, and now I tend toward less harsh, more nuanced songs. One of my great joyous discoveries in recent days has been the series of Voices Only and Voices Forte series of recordings of a cappella groups. I sang in choir in grade school, high school and college, so group vocals takes me back to some lovely times. 

I'm guessing much of this is a function of aging, but the equipment has solidified strong desire to hear it.