As inconceivable as it seemed in the late '70s and '80s, when he bestrode the musical world like a chicken-fried colossus, Willie Nelson has become something of a trivia question to many of the inhabitants of the world of '90s country music. Not in Austin, mind you, where "In Willie We Trust'' might as well be engraved on the municipal letterhead, and mystics occasionally report the mysterious appearance of his beatific visage on fresh-baked tortillas. Nor in Texas as a whole, a state with an enduring taste for eccentrics with a twinkle in their eye.

But there are younger country music fans in the hinterlands and not-so-young executives on Music Row in Nashville who are apt to shrug "Willie who?'' when the outlaw patriarch's name is brought up.

To the casual observer, the skeptics make a good case: Having lost his berth at Columbia Records in 1993, Nelson has seemingly drifted at whim, recording marginally selling albums for a variety of smaller labels. His latest (his third for Justice Records, the Houston-based indie label) is a re-release of his 1971 concept album, "Yesterday's Wine.''

His songs are nowhere to be found on the mainstream "Hot Young Country'' radio formats, and at 64 (he is old enough to recall the birth of Social Security; next year he will be eligible to collect it), Nelson is deemed hopelessly inaccessible to the demographic tail that wags the dog of the radio and record industries these days.

His Fourth of July Picnic, once a unique, Lone Star-waving gathering of the tribes, has shrunk to a vestigial ritual that keeps regenerating itself for no particularly compelling reason (the latest edition -- the 25th anniversary Picnic, by rough count -- will be held tomorrow in Luckenbach). The Picnic, featuring a graying cohort of Nelson familiars, pales in scope and charisma next to 100,000-strong bacchanalias Nelson used to assemble on Independence Day (a far cry from the bloated, corporate-sponsored mega-festivals, like last month's CountryFest up near Dallas, which are the fashion today).

His concert set, as this listener of 20-plus years will attest, has not changed in essence in decades.

The skeptics will tell you there is less and less reason to pay attention to WillieNelson: Ain't it funny, they'll tell you (before moving on to anoint the next Flavor of the Month), how time slips away?

Well, the skeptics are full of sheep dip.

WillieNelsonstillmatters, in ways that Soundscan sales charts and radio Arbitron ratings can't measure. (I would have been happy to address questions of his ongoing relevance to Willie his ownself, except that he was away in Hawaii and on the road; efforts to cross paths with him by phone proved unsuccessful).

If he doesn't put hits in the Top 10 like he once did, he remains one of the last repositories of iconoclastic vision and unfettered imagination to which country music has access.

Texas has conjured up such prodigies in the past, in many musical disciplines -- Scott Joplin, Ornette Coleman, Bob Wills, T-Bone Walker and Janis Joplin all achieved renown by breaking down barriers and forcing listeners to confront music on the artist's terms.

This has been Willie's particular genius as well. Listen to him for any length of time and his music -- filtered as it is through the lenses of blues, country, jazz, American pop standards, folk and gospel -- emerges as a clear and cogent creative vision informed by all these influences but constrained by none. Suddenly, the listener is viewing the musical landscape through Willie's panoramic perspective.

Consider his last major-label album, 1993's wonderful "Across the Borderline, '' an ostensibly "country'' album which blends songs by Paul Simon, Willie Dixon, Ry Cooder, Lyle Lovett, Bob Dylan, Peter Gabriel and Nelson himself.

Coming from almost any other artist, this shotgun wedding of genres and tunesmiths would have come across as a mishmash born of unchecked egotism. But Willie weaves the disparate strands into a coherent tapestry, which engages the listener with a sort of organic inevitability that is immensely satisfying. "It's always time to stretch, '' said Nelson modestly at the time of the album's release, hardly needing to add that stretching has been a way of life with him.

"Spirit, '' his understated 1996 album on Island Records, achieved much the same effect in a more low-key fashion, folding flamenco and mariachi textures into a suite of songs that glow with luminous spirituality. We are told that Nelson has a blues album and even -- Gawd! -- a reggae album in the can awaiting the light of day. Well, why not?

It's harder and harder to find anyone in Nashville (or even on the self-consciously left-of-center Americana chart) who will roll the creative dice with the same aplomb that Nelson has displayed for at least a couple of musical epochs.

But that effortless eclecticism is only half the story. At an age when many artists have entombed their work in CD box sets (funny how much those things look like coffins ...) and content themselves with collecting royalty checks, Nelsonstill displays an energy, an imagination and a restless curiosity that is the envy of musicians half his age.

Hey, don't take my word for it; let's go to the tale of the tape, as the boxing writers used to say.

There are the classics he has authored -- from "Crazy'' to "Night Life, '' "Hello Walls, '' "Funny How Time Slips Away, '' "Three Days, '' "Angel Flying Too Close to the Ground'' and a score of others -- songs whose blues-inflected phrasing (a Nelson signature) and dark and stately lyricism would enthrall singers from Patsy Cline to the Supersuckers over the course of the years.

The aforementioned "Yesterday's Wine'' was but the first of four concept albums that examined everything from a crumbling marriage to spiritual redemption and reincarnation. The most celebrated of that quartet, "Red Headed Stranger, '' boasts a permanent place in any Top 10 Country Albums of All Time list.

Almost as an afterthought, Nelson created an album of standards, 1978's "Stardust, '' which has become a standard unto itself. He has recorded with everyone from Faron Young to U2's Bono. His ongoing Farm Aid concert series endures as a populist-based Middle American landmark.

But the resume doesn't tell the whole story.

Resumes are ossified, static; Willie is anything but. "I can be moving or can be still, '' he once sang, "But still is still movin' to me.''

"The most challenging thing, '' he once said, "would be to come up with something entirely different that I haven't thought of yet, and do it before I have a chance to think about it, and back out.''

Kris Kristofferson once said that Willie's face belongs on stamps and money. His point, in part, is that Nelson embodies the best of everything that an artist should bring to the table: vision, chops, commitment, imagination, compassion, restless energy, fresh perspectives and a joie de vivre thatfinds its fullest expression in the creative process.

For those reasons, and for many others, Williestillmatters, and always will.

So even if you're not at Luckenbach tomorrow, pour a tequila shot and hoist a toast to WillieNelson. They ain't making any more of him.