Despite Star-Lord getting most of the heat for the defeat of the Avengers understandable considering what he did!) there has been a lot of thought on decisions that were made by certain superheros that lead to Thanos‘ victory. In particular, had Tony Stark and Doctor Strange returned to Earth as oppose to continuing onto Titan, the Avengers were more likely to win the Infinity War.
After saving Doctor Strange from Ebony Maw’s torture, Iron Man, Strange and Spider-Man were left on his ship deciding their next move. Whilst Strange was convinced that returning to Earth will guarantee the Time Stone’s safety, Stark was determined that going to Titan will bring the element of surprise.
However what this move ultimately did was split up the Avengers in two different places and made it far easier for Thanos to get his hands on the Infinity Stones. Had they returned to Earth, a full force of Avengers would’ve meant that Thanos would have to defeat them all at the same time.
Not only that, but it would’ve meant that Thanos would’ve entered Wakanda with only four Infinity Stones as opposed to five, making it a lot easier to defeat him. Considering how close they were to defeating him on Titan with just a few Avengers, it is not a far fetched thought to say that they could’ve beaten Thanos on Wakanda with the full gang had Stark been on board with Strange’s initial plan.