The Hulk had only lost the use of one arm; his other arm was still fine. In any case, he should have been able to withstand it one more time, right?
Then wouldn't Tony have survived?
Even if the Hulk couldn't endure it, weren't there still the God of Thunder and Captain Marvel? They should have been able to, right?
Electromaster: "Could it be because there was no Infinity Gauntlet?"
Son of Nature: "That possibility is relatively unlikely."
After all, under normal circumstances, inventing something was difficult, but manufacturing it based on existing documentation was not particularly hard.
Since Tony Stark had already created the nanotech Infinity Gauntlet, he surely left behind the relevant manufacturing methods. Building another one based on that information would not have been difficult.
With Wakanda's technological prowess, replicating a nanotech Infinity Gauntlet should not have been impossible either.
If that still didn't work, he could just travel back to before Tony had made up his mind to deal with Thanos and have him make one.
So the most likely reason was still plot settings.
Tony Stark: "...This damned plot."
You all only thought about letting the person roleplaying me retire. Why couldn't I get a good ending?
Uchiha Dance King: "So strength is still the most important thing."
Uchiha Dance King: "These past few days, I have already begun searching for Jinchuriki to extract their Tailed Beasts."
Uchiha Dance King: "Once I reach the Six Paths Level, it will be time to head to the moon and recycle that Tenseigan."
Uchiha Dance King: "Across the Myriad Worlds, the Six Paths Level is still far too weak."
Whether it was the Angel Civilization of the Super Seminary world, Tony Stark's Marvel World, or Mikoto Misaka's A Certain Magical Index World, his strength was far too insignificant