One fears that the good folks in Hollywood California -- even with mandated, universal health care -- can pull this movie off.

At the risk of fanning the flames, does the cartoon have a point about comparative advantage?

I heard the movie was going to be a trilogy, shot Lord of the Rings style (all at once, but released separately)

Besides, how did the strikers eat in Galt's Gulch? Surely there was a market of some kind.

(been a while)

Yes, AC, the trilogy or not to trilogy story is referenced in the "Atlas Shrugged Movie" link above.

How did the strikers eat?

"I'll leave you to do it," said Galt, "while I go to the market to get supplies for breakfast."

[...]

He rose to cook the rest of their breakfast. [...] When he put her plate before her, she asked, "Where did you get that food? Do they have a grocery store here?"
"The best one in the world. It's run by Lawrence Hammond."
"What?"
"Lawrence Hammond, of Hammond Cars. The bacon is from the farm of Dwight Sanders—of Sanders Aircraft. The eggs and the butter from Judge Narragansett—of the Superior Court of the State of Illinois."
She looked at her plate, bitterly, almost as if she were afraid to touch it. "It's the most expensive breakfast I'll ever eat, considering the value of the cook's time and of all those others."
"Yes—from one aspect. But from another, it's the cheapest breakfast you'll ever eat—because no part of it has gone to feed the looters who'll make you pay for it through year after year and leave you to starve in the end."
After a long silence, she asked simply, almost wistfully, "What is it that you're all doing here?"
"Living." -Part 3/Chapter 1, Atlantis

And New York City was NOT "on fire:"

There were not many lights on the earth below. The countryside was an empty black sheet, with a few occasional flickers in the windows of some government structures, and the trembling glow of candles in the windows of thriftless homes. Most of the rural population had long since been reduced to the life of those ages when artificial light was an exorbitant luxury, and a sunset put an end to human activity. The towns were like scattered puddles, left behind by a receding tide, still holding some precious drops of electricity, but drying out in a desert of rations, quotas, controls and power-conservation rules.
But when the place that had once been the source of the tide—New York City—rose in the distance before them, it was still extending its lights to the sky, still defying the primordial darkness, almost as if, in an ultimate effort, in a final appeal for help, it were now stretching its arms to the plane that was crossing its sky. Involuntarily, they sat up, as if at respectful attention at the death bed of what had been greatness.
Looking down, they could see the last convulsions: the lights of the cars were darting through the streets, like animals trapped in a maze, frantically seeking an exit, the bridges were jammed with cars, the approaches to the bridges were veins of massed headlights, glittering bottlenecks stopping all motion, and the desperate screaming of sirens reached faintly to the height of the plane. The news of the continent's severed artery had now engulfed the city, men were deserting their posts, trying, in panic, to abandon New York, seeking escape where all roads were cut off and escape was no longer possible.
The plane was above the peaks of the skyscrapers when suddenly, with the abruptness of a shudder, as if the ground had parted to engulf it, the city disappeared from the face of the earth. It took them a moment to realize that the panic had reached the power stations—and that the lights of New York had gone out.

[...]

They could not see the world beyond the mountains, there was only a void of darkness and rock, but the darkness was hiding the ruins of a continent: the roofless homes, the rusting tractors, the lightless streets, the abandoned rail. But far in the distance, on the edge of the earth, a small flame was waving in the wind, the defiantly stubborn flame of Wyatt's Torch, twisting, being torn and regaining its hold, not to be uprooted or extinguished. It seemed to be calling and waiting for the words John Galt was now to pronounce.
"The road is cleared," said Galt. "We are going back to the world."
He raised his hand and over the desolate earth he traced in space the sign of the dollar. -Part 3/Chapter 10, In the Name of the Best Within Us

Hmm. I think they'd have been better off bringing David Ricardo and a boatful of illegal aliens than to have their most productive citizens stocking shelves and raising livestock.

This is why I am a Rand fan and not an Objectivist. You can't go to the food court of ideas and eat at the Chinese place everyday, even if it's good.

The purpose of hiding out in Galt's Gulch was not to create a replacement society. It was to withold life support from the terminally ill society they abandoned. If they could achieve their greatest potential in the valley they'd have no reason to return. Important reasons to return include natural resources, larger markets and, yes, lower cost labor.

While you're at the "food court of ideas" you'll do well to avoid the pizza place with arsenic in its sauce and the taco stand that garnishes everything with rat poison. With ideas, as with food, follow Heinlein's advice: "Everything in excess! To enjoy the flavor of life, take big bites. Moderation is for monks." But swallow only food. Learn how to recognize poison and learn why not a single drop must pass your lips.