And yet, by the same token, virtually every 'critique' of a mix I've seen that involves a lead instrument playing while the lead vocal is happening offers up the same advice - "it's too busy, lose the guitar/flute/sax/whatever"....
....much of the advice given shows that actually, most of us are pretty 'standardized' in our own way.
Yes, but the way one un-clutters a mix is a creative decision within the context of that mix. One listens to the mix and then makes adjustments based on that and where they want the mix to go. There isn't just one way to un-clutter a given mix.

A plug-in/preset can't hear the mix, is not making an artistic decision within the context of that mix and has no clue where the mix needs to go.
Sure, the preset will give you a "result", and it may even sound OK, but the danger lies in the "crutch" aspect of using the preset approach, especially with newbies who are MILES away from really knowing what they are doing...and so that preset shortcut becomes their "experience". They often accept that stuff as the final step of their own decision making process and do not learn or discover anything more.
His end quote was one I've never forgotten - "In the 60s, we created sounds. Nowadays, people select sounds".
I think George was talking more about selecting presets as in synth sounds, etc or pre-constructed FX....where back in the day, they conjured all that stuff from scratch....and I have to say, a lot of folks DO just use presets, as-is.
Sure...many of them actually sound pretty good, but then what happened to imagination and creativity? The guy who created the presets had them...the guy who just calls them is merely ordering from a menu...he's not doing any of the cooking.

That may be OK for some people....but yeah, like you pointed out, there are many who prefer to create stuff from scratch, and yes, it's hard and time consuming to do that, and THERE is where this "That Was Easy” button mentality is anchored. Lots of folks are simply looking for quick-n-easy and don't desire to invest a lot of time and energy into it...yet they still want a polished product.
Paint by the numbers or start with a blank canvas. I guess everyone needs to pick their preferred method.