system
Given the following post, respond as if you're commenting on Reddit:
human
[Captain America: The Winter Soldier] what would the following couple days look like had Cap not succeeded in taking down the Insight Helicarriers?

And on a related note, what exactly was Hydra trying to accomplish? Sitwell told us that the carriers were to eliminate people who could stand in Hydra's way, but that sounds more like a safeguard than a goal to me.
gpt
Tens of thousands of people would have died within a matter of hours, struck down by a blast from a helicarrier cannon.  The internet and news organisations would have exploded initially with wild stories and panic. Soon, however, the most important counter voices would be eliminated and replaced with HYDRA propaganda.

"Remain calm, go home and stay there," would be the commands.  Many people who would've disobeyed and questioned this new authority would already be dead.  

Over the next few days HYDRA would begin feeding the public with their new directives.  Emergency services would go about cleaning up the messes created by thousands of cannon strikes.  People would be stunned and afraid.

However, it would turn out that an algorithm for human behavior written by a 100-year-old Austrian would be woefully inadequate in predicting the reactions of modern populations to mass catastrophes.  New leaders would begin to arise. 

 Disparate elements of SHIELD would survive in secure bunkers and with scrambler tech.  Within the first 48 hours they would coordinate a counter strike and destroy the helicarriers.   HYDRA simply would not have the manpower to protect their initial gains adequately.  Then, due to its nature, HYDRA would fragment in factional infighting with groups trying to use the chaos as an opportunity to grab power.

The world would be in shambles.  Civil wars would flare up in many countries as SHIELD got the word around about what was happening.  HYDRA would control many governments and use their resources to hunt down opposition elements, but being accustomed to operating in the shadows, they wouldn't be particularly effective in overt control. SHIELD, being in its element of stealth and subterfuge would have the advantage in sabotaging HYDRA's new-found power where it could.