Also it's overly simplistic to say pharma companies are making "billions" off her cells. HeLa is a part of the workflow but far far far from the only part. Also value is in the work of scientists understanding the cell biology using her cells as a model, not some inherent value in the particular genome of HeLa.
If I recall correctly they had been trying to grow a cell line for years. Her cancer had a specificity that made it possible.