...struck with the feeling that a musak version of "Living in the Past" by Jethro Tull is highly unnecessary. Mainly because it doesn't sound any different from the original...

Don't worry. Ian Anderson thought the same thing. In one of the Jethro Tull box sets (25 years, I think), he introduces Living In The Past something like this: (not an exact quote, this is from memory, but it will be pretty close...)

...Here is an oldie that we have utterly loathed for fifteen long years. But now it is back, rewritten in a slightly trickier form making it more fun to play. It's called Living In The Past...

The beginning and the end are still very muzak-ish, but the center there is a lot of improvisation and good stuff.