There will never be a shortage of helium. Only a shortage of really cheap helium.
Helium is continuously produced by alpha decay of radioactive materials inside the earth. It exists in various concentrations in all natural gas reserves.
Some of those reserves (e.g. some wells in Texas or the one now found in Tanzania) have unusually high helium concentrations, making production costs much lower. The U.S. government used the Texas wells to set up a strategic reserve in the early to mid 20th century (when zeppelins were still a thing, and later for the space race).
Towards the end of the 20th century, it gradually sold this inventory into the market, effectively subsidizing it with tax paid by americans during the cold war. This created a disincentive for developing the capability of producing helium from lower grade sources. The uncertainty in the market raised prices, based on the perception of an impending shortage.
Without the Tanzania find, the increased price would have eventually convinced someone to invest in the infrastructure for separating helium from lower grade sources, eliminating the dependency on the chances of finding high grade sources.
Of course, if someone *had* done so, he would have been greatly disappointed by the Tanzania find reducing the price hurt the return on their investment. That's the risk of investing.