Via The House Next Door, whose commentors do a better job at this than I could.
Thus this question: How did a man with no interest in the fundamentals of film get taken seriously for as long as he did? I'm not arguing that the well-made Hollywood movie is the only possible filmmaking mode. The likes of Renoir, Bergman, Buñuel decisively disprove that notion.
But the greats all share intentionality, the need to direct our attention to something that was on their minds. They did not leave their people flopping around until something printable happened.
-Richard Schickel; Book Review - Robert Altman: The Oral Biography by Mitchell Zuckoff
To say that Schickel misses the point is a little simplistic, but he certainly doesn't understand what continues to make Altman so interesting and, as one of the comments at The House Next Door notes, "still polarizing long after his contemporaries' films are safely, nostalgically respectable," which is exactly the fact that his intentions were rarely clear, especially in the 70s. It's exactly the sloppiness, contradictions, misdirection, ambiguity, and total disinterest with the any mode of storytelling that makes Nashville one of the greatest films ever made, McCabe and Mrs. Miller one of the loveliest, and The Long Goodbye one of the most fun.
My last semester at college, I took a class called The Hollywood Renaissance, which dealt with American cinema from the late 60s through the 70s. We watched the usual suspects - Taxi Driver, The Godfather, Bonnie and Clyde, The Conversation...all of these received a real united reaction. With the exception of one or two people, we all loved them. The most polarizing film was, by far, Nashville. A strong contingent of us felt it was a truly startling, unsettling piece, perhaps the most important piece of the entire movement. The other half found it aimless, boring, wrote it off because "nothing happened."
It's fascinating how, decades later, the content of these films rarely matters. For all the hullabaloo in their day over their violence, the films noted above are as safe now as Casablanca (which is not to dismiss...I love Casablanca). We watched a handful of films that would still be considered radical - Easy Rider, Wanda, Two-Lane Blacktop - but that label doesn't apply because of anything that happens in them, but rather the way they happen. Scorsese, Coppola, and Penn are all fine directors. Often great. But with their most important work, they were only telling new types of stories. Altman was interested in telling stories in whole new ways, or even on occasion not telling stories at all, and THIS is what made, and continues to make, him radical. Not his frequent use of nudity or profanity or anything else.
Really, if you haven't seen them, I can't recommend enough that you go out and watch Nashville, McCabe and Mrs. Miller, and The Long Goodbye. Better yet, start with The Player, which is far most accessible and traditionally entertaining. It was the first film I saw of his that really made me sit up and go, "who is this guy?"