system
Given the following post, respond as if you're commenting on Reddit:
human
[MCU] How would the events of the rest of the movies would have changed if Ultron had worked as intended and protected the world?

Edit: I see that some people misunderstood the question. I meant if Ultron had worked as Tony intended (as a peace keeping program), not what would have happened if he succeeded nuking the Earth.
gpt
Well if Ultron hadnt been based on an alien AI with unknown utility functions (core values), it would be like the end of IM3, but the suits would never mis-identify a hostile target (like how they mistakenly targeted Pepper as she presented as an Extremis terrorist).  

So what would change if there were thousands of Iron Man armous policing the world? 

So AoU never occurs - so Sokovia stays an unknown country, there are no accords, Helen Cho still has a tissue printing machine which can mend 90% of the worlds medical issues, Scarlet Witch and Quicksilver remain Hydra assets, Zemo has no reason to attack the Avengers, Stark never learns of the Winter Soldiers involvement with his parents death.

Basically *all* the relationships change, *all* the following films change.  

Would the Ultron weapon project be enough to prevent Thanos?  

Hard to say - on the one hand it would provide a huge bonus to the weapon systems defending the world, but on the other hand it would just take *one* alien with the ability to hack the system to go all hydra project insight on Earth, turning our weapon systems against ourselves.