There is hardly any doubt that True West draws its energy from the dynamic tension in his own mind between acting and writing, stage versus screen, the demands of a public persona versus his needs for privacy. Clearly, Lee and Austin correspond to two sides of the Shepard known to the audience. Yet, the theme "double nature" goes through the whole play.
The image of the West is depicted to have a double-nature itself: on one hand Austin says that the West does no longer exist, on the other hand he longs to go there. It is ambiguous in other ways as well: the "civilized, industrialized west" of LA on one side and the rough, wild west of the desert on the other side. Both are present in today's California.
Austin represents the west that is corrupted by the Hollywood movie business, which only has  the artificial Hollywood made reality. Lee is the pure talent, who speaks from his own experience. This represents also the two sides of Shepard himself.

The other major theme is the quest for identity and roots. Both characters want something more profound and authentic than what is currently offered in our culture, each envies the other and becomes what he criticizes on the other. Austin’s responsibility and middle-class dream is seen to be as foolish as Lee’s drifting and adventurous lifestyle. The conflict is unresolved. Both are trapped in the uneasy, soul-sucking quagmire of the Southern California West. Shepard shares with his characters their quest for identity,  and doesn't seem to find a satisfying one.

In the West rootlessness is far more widespread and for many almost the condition of life. But at the same time the West, particularly California, is the place where, most acutely, visible success, gestures of self, personality, fame are means, conscious or not, of making up for or disguising the lack of roots. The destructive effects of family relationships in an ailing American society, family breakdown.

How is "The West" depicted in the play?

The story suggests that the myth of the West, the heroic loner surviving gloriously on the frontier, is a sham. The true west is a shabby and diminished place for which an appropriate image is a drunken old man losing his false teeth in a bag of chop suey. The truth is, it suggests, that the American west – whether urbanized or wild – is an undifferentiated landscape of frustrated desire. Lee’s notion of getting back to grips with the earth is as much an internalization of empty media myths as Austin’s desires. The frontier America which Lee dreams of no longer exists, if indeed it ever did. He is forced to admit that his entire wild-man persona is simply a posture, a fake, and that he was driven out to the desert not through choice but through failure "because I can't make it here".

 The West is not so much a place, as a state of mind. For Shepard, the landscape itself is internalized within the play’s kitchen setting and the rocky relationship between the brothers. It is as if Shepard is telling us that violence and sleazy film-making are the True West. Violence is very much validated in True West. Delight is taken in destruction, it need not have a discernable motivation. The room’s condition pretty much reflects the characters’ sibling rivalry escalating into psychological warfare.

Shepard depicts a society which ignores its own history and heritage in favor of a constructed mythology which is largely derived from the cinemas,  thereby American society and individuals are able to reduce the ambiguities of modern life. American society is crippled, because it is rootless, incomplete, vacuous. The past is seen to catch up not only with the individual but also with the family and, by intimation, with American society and culture.