As you mention, many rockets, including SpaceX's Falcon 9, use Helium for pressurization. But newer designs, including SpaceX's Starship rocket, hope to eliminate its use and use autogenous pressurization instead.
In part, this is because the falling cost of rockets has magnified the relative cost of Helium. Just more evidence that progress reduces costs and solves the scarcity problem across many dimensions.
As you mention, many rockets, including SpaceX's Falcon 9, use Helium for pressurization. But newer designs, including SpaceX's Starship rocket, hope to eliminate its use and use autogenous pressurization instead.
In part, this is because the falling cost of rockets has magnified the relative cost of Helium. Just more evidence that progress reduces costs and solves the scarcity problem across many dimensions.