Movie conceits

How come in Hollywood movies, when you turn on the TV, whatever you are interested in seeing on the news is always on at that moment?
Or that if you need a cab, you just go to the curb and raise your arm, and you have one within five seconds?

Not even the worst novelist would write stories like that, and it may be part of the reason some people have trouble respecting Hollywood. (Not me though.)

Update: Featured comment by Pascal:
Actually, this is one of the ideas I've already written down for later use. Once, I saw an "action" movie that was so pathetic and cliché, that I considered writing a novel version of it, in a sarcastic tone. It would go something like this :

"The poor, foolish Pitystani rebels! Challenging Brad Brannigan like this on a bad hair day! He jumped from his cover in disdain, and calmly walked forward to the fortified HQ, one heavy machine gun in each hand, spraying the charging fanaticized enemies and mowing them down, wave after wave, sneering at the hail of bulets which kept missing him by a mile, their years-long brainwashing hardly a match for the holy panic that his mere heroic sight filled their bearded hearts with.
The mortar shells falling all around him in clouds of smoke didn't even make him flinch. He was a one-man army, out for revenge, justice, and the American way. His Ray-Bans glistened superbly under the faint crescent moon's light. His machine guns empty, he paused and looked at them while the soldiers kept firing at him, so intensely that he had to take a small step sideways. He tossed them on the dusty ground, took out his gun in one hand, and started making ammo count by downing at least three foes with each bullet, not bothering to really aim, while tossing grenades like baseballs, each one sending a dozen commies screaming in the air. His red-hot handgun jammed after the 75th bullet, so he grabbed his trusty army knife, and plowed through the hordes of heavily armed terrorists, all way too terrified to even think of opening fire before he came close and cut them in half with his casual swings. The deaths of his whole platoon would soon be avenged. Smith, Jones, Jackson, Sanchez, Lee... All those beloved generic characters would not have died in vain.
But for what he did to his goldfish, Bou Guimahn would suffer. A lot. His knife would lose its edge before he got to the scumbag, but he still had a broken toothpick in his front pocket. The Metal Gear nuclear tank of the infamous villain didn't stand a chance. Its radar could only lock on metallic weapons..."
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Eolake again:
One of my friends stopped watching action movies with me because I always predicted who'd die. If they are too nice, have no important function, and especially if they have doubts, they are dead for sure.