Action movies have been popular almost since the beginning of films in general, with a number of action heroes emerging in westerns, which were the precursor to the more intense action films of today.
Ever since the days of Tom Mix, Hopalong Cassidy, and John Wayne, people have been fascinated by the thrill of watching chase scenes, fight scenes, and the strong interplay between good and evil, all set against spectacular backdrops. A big boost was given to action movies by the James Bond series of films, in which the stakes were often raised to include global threats, and the hero often dispatched the bad guys as often with his wit as with his fighting expertise and gadgets.
Early action films
Some of the earliest true action films coming from Hollywood occurred in the '60s and '70s, when Bullitt, The French Connection, and Dirty Harry set the tone for elaborate chase scenes through metropolitan areas, and strong heroes were on hand to deal with the criminals.
Then in the 1980s and '90s, several actors extended the action film genre to include themes other than cops chasing criminals. Sylvester Stallone started the Rambo series about a solo American soldier who never quite left the war, and he also found favor with his Rocky series, which focused on an underdog boxer with a big heart.
Arnold Schwarzenegger traded on his popularity as a bodybuilder to produce a whole slew of action films, with widely varying themes. Virtually all of his action films were popular, including everything from The Predator, where he fought an alien hunter, right up to The Terminator series of films, in which he played the role of a non-human hero who was initially the enemy, before having a change of programming and becoming one of the good guys.
Bruce Willis was another actor who became extremely popular in action films, beginning with the critically acclaimed Die Hard movie. That movie was so good that it spawned several sequels, and is being considered for a franchise re-boot, by Disney, who now owns the rights to the films.
Any number of other action heroes were originated in that same period, including some martial arts experts like Steven Seagal and Jean Claude Van Damme, both of whom enjoyed popularity from a string of movies they appeared in.
Modern action films
Hollywood has not abandoned the formula for successful action films, since today's most popular action films generally include the same kinds of chases, explosions, and liberal use of modern technology, as the earlier action films did.
Hollywood filmmakers have been heavily influenced by Asian films which feature more martial arts sequences, but in general, the formula is the same now as it was when the first cowboy rode across the western landscape. Film goers still enjoy seeing the good guys chasing the bad guys, ThePirateBay encountering all kinds of obstacles along the way, and eventually overcoming all of them to prevail over evil.
The settings may change, and the technology always improves, but the general formula remains intact.