For Beirut shoeshiners and taxi drivers, a feeling that no one cares

Beirut, minus the American Marines, is a city that has lost hope, a city that feels betrayed. The signs are everywhere: in the voices of ordinary men and women, in the strident anger of usually more detached Lebanese political analysts and journalists. . . .

Or at a remarkable art exhibit that just opened amid the shellfire and uncollected garbage of west Beirut. One striking montage centers on a photo of the shattered United States Embassy here, car-bombed 13 months ago. The title: The April the Flowers Died.

Most among Lebanon's unarmed and thus powerless majority seem convinced that the embassy bombing marked the inevitable beginning of the end of a direct US commitment to putting Lebanon back together.

''Reagan should have ordered the bombing of the Syrian presidential palace or the Defense Ministry in Damascus right then and there,'' explodes a Beirut intellectual who is usually soft-spoken.

But for the less intellectual - the shopkeepers, shoeshiners, or taxi drivers - the whys and wherefores of the US retreat are not what matters.

''It is the feeling,'' says Michel Zugaib, ''that now that the Marines are gone, no one in the world is listening. That no one cares. When the Marines . . . were here, this place was crawling with journalists. Not any more.''

A plumpish woman who works as a telex operator is yet more bitter. Partly, she explains, ''I'm upset because my sister has had a nervous breakdown. Her son was injured in some shelling. The son is OK now, but my sister literally goes crazy any time any one of her children wants to leave the house now, even to go to the grocery store.''

Lebanon's bloodletting, she acknowledges, is not the ''fault'' of America, of its president, or of its Marines. Beirut, after all, is entering its 10th summer of a civil war that began long before the Marines' arrival as ''peacekeepers'' in 1982.

But the point, he says, ''is that the Americans should not have come here at all if they were going to leave us like this. They should not have allowed us to hope. . . .''

Hope is a commodity civilian Beirutis feel can be only imported. The typical response to the frenetic workings of a newly installed ''national unity'' government is a bitter guffaw, like the one delivered by a taxi driver here named Issam. The key to ''real peace,'' say Beirutis of all sorts, must lie outside. That's where the money and guns for Lebanon's rival Christian and Muslim militias have been coming from, they reason.

On the face of it the Israeli-Syrian equation of late should provide a sliver of hope. The Israelis are visibly seeking a way to pull out at least partly from south Lebanon. The Syrians, for their part, have helped install the new Lebanese government.

So what's the problem? A prominent Lebanese political analyst offers the typical reply: ''The Israelis and Syrians are still very much rivals in this area, for one thing, and the natural place for that rivalry to explode remains Lebanon. But there is also the question of the political situation in Syria in the wake of President (Hafez) Assad's hospitalization last year.

''There have been clear signs of tension among his potential successors. . . . The key to everything here in Lebanon is how good Assad's health is at present. No one really knows. But until the situation is resolved, Lebanon cannot become truly stable.''

Beirut, meanwhile, agonizes. Sometimes the shellfire between the city's Christian and Muslim sectors is heavy. Sometimes it is relatively light. When the shells stop, sunbathing and seaside suppers take their place.

''I go to the beach to escape,'' explains a tanned Micheline Hazou. ''It is our only escape these days.''

The central fact about Beirut, says another woman, is that violence has become the norm here - like the black-bordered posters of the youngsters who have been killed. Or the candle settings at the Spaghetteria Restaurant: The colorful wax drips not on the expected empty bottle, but on an odd array of spent mortar casings.