Helium is abundant in the rest of the Universe, but relatively scarce here on Earth. The reason? Helium can escape Earth’s gravity and dissipate into outer space.
Helium is also non reactive. Hydrogen escapes easier than helium but much of it is bound in other molecules.
Helium most likely is the result of alpha particle emmissions from radioactive decay and accumulates as a gas in natural gas reservoirs. That statement is without support and just my guessing.