Is improvisational jazz to impressionism art as smooth jazz is to realism art?

@edcyn- +1.
Bill Hart

Not sure I am following your analogy. Are you saying smooth jazz is more like photo realism in painting? And that improvisational jazz is more like impressionism? I’m not sure I’m capable of answering that.
I was not listening to jazz for years, despite having shelves of straight-ahead stuff, some of it considered "important," but what got me going again several years ago was stuff in the ’70s done by some of the players who had serious credentials but no market. So, what I began to explore was more eclectic, personal, less commercial stuff that eventually became very collectible because it was only issued in small runs by small or private labels. Strata East and Nimbus West come to mind-- some great material on those labels.
Cecil McBee became one of my favorites- a very melodic bass player who appears on a lot of so-called spiritual/soul jazz and some stuff that is classified as "free jazz." I don’t like complete cacophony, but appreciate it more as an accent or element of contrast -- Pharoah Sanders is known for this multi-phonic squawk from his horn but he can slide back into a melodic line which hits the center of the sweet spot in a way that is sublime.
There’s a lot out there to explore. I think one of the virtues of modern jazz (or any type of music for that matter) is that you can educate yourself by listening and the process is pretty enjoyable. And there’s a fair amount of information out there to tap into.
For me, it isn’t an intellectual pursuit, or one that I consider an investment. But, the more edgy stuff is something I have "ears" for now, partly due to exposure and digging down into a vein that has proved to be rich, e.g. McBee’s work. I guess I like straddling the line between what would be considered post-bop and "free" jazz, although I’m always happy to listen to Art Pepper (Cecil appears on one of his late records "Today"), or Bud Powell or other greats from the earlier eras.

Nice post, @deadhead1000- I don't think anyone seriously thinks they can convince a person to like a certain type of music, and the added difficulty with jazz (not quite as much as a factor with rock during its heyday) is that jazz performers appear on lots of records as non-featured artists. To a lesser degree true with rock, but some of my favorite work is actually that of the side persons/session players on a given recording. 
I grew up around people who would follow the Dead; my listening of them told me they were consummate, and could jam blues/folk/rock/ endlessly at a high level of technical and musical proficiency, but it really is a long trip, isn't it? (Some of these jazz tracks are entire sides, not making that a measure of anything). 
On Tull, having come up on them from the beginning, "Stand Up" is so much the template for what that band did in creating a men in tights medieval balladeer meets crushing rock (the guitar wielded by Martin Barre was pretty gnarly); This Was is more blues and jazz and doesn't reflect the general direction of the band (though Aqualung, commercially and musically, may be the album of broadest appeal). But, at the end of the day, just using that band as an example you can find different periods associated with different overall sounds/styles from the band. Sometimes, your point of entry affects your perception, too. 
In connection with jazz, I really didn't pay any attention to any of these records at the time they were released. They were only discovered by me after many excursions into more unfamiliar terrain, sometimes, with knowledge of one or another musicians who appeared with them for that particular recorded performance. 
Maybe my mantra should be listen more, talk less. But, then you'd never see me. :)

Just like any other genre, it breaks down at a certain point. You could go into funk, or fusion, traditional or period, and within period (much respect to the players I mentioned above-- the people that made these recordings in many cases were the real unsung heroes); you like what you like. 
As I mentioned, I got back into jazz in say the last 5 years largely because I was enjoying the music, both composition and performance (as well as the recording) of more offbeat stuff. My direction isn't yours or anyone else's. But it affords me with an entire body of material that I've found rewarding through further research and listening. As well as the acquisition of older copies of records or at least a preferred reissue if one exists. 

Sorry but have not read all the intervening posts. Interesting jazz, to me, ranges from the bass viol part on side 2 of "Marchin' On" by the Heath Bros on Strata-East to hearing yet another rendition of "Patricia" by Art Pepper, with Cecil McBee, Roy Haynes and Stanley Cowell. There is so much out there, and even with effort, I've only scratched the surface. 
Buying them as LPs is a thing unto itself. 

I already provided my view on improvisational or more challenging jazz upthread. I will say that from my limited view of streaming services Qobuz, for example as a trial, it isn’t very deep in jazz. Look up Cecil McBee, who I keep mentioning, and see how little you find. Compare that to his discography, as listed by Discogs (which is crowd sourced and may include mistakes).
The groove-- what turns you on-- is where you find it. For me, a lot of that may depend on mood, which is a whole separate thing from quality of performance, recording, mastering or pressing. I will say that Eddie Hazel is criminally underrated. -Maggot Brain- you’ll need no convincing.