Pharmacogenetics - FDA is working to develop PGx tests to help drugs remain on the market

I'm still trying to understand if pharmacogenomics will help creating new drugs or it will just be a way to make old drugs remain at the market. Reading the article "The 5 Myths of Pharmacogenomics" Oct 1, 2003 By: Stan Bernard, MD, MBA Pharmaceutical Executive I'm confronted with many arguments such as:

"For example, in 1998, FDA forced Hoechst Marion Roussel (now Aventis) to withdraw its $600-million-a-year anti-allergy medication Seldane (terfenadine) from the market because of pharmacogenomic differences in a very small segment of patients. Fewer than 0.5 percent of all people have a variant CYP3A gene that makes them unable to metabolize Seldane in the presence of the antibiotic erythromycin, resulting in severe cardiotoxicity. If the company had had a pharmacogenomic test to identify the small population of adverse reactants at the time, Seldane may have remained on the market. Consequently, Aventis was forced to focus its marketing efforts on another anti-allergy medication, Allegra (fexofenadine)." (emphasis mine)

"To rescue the product's $200 million in annual sales, GSK is currently working with FDA to develop a PGx test to identify patients likely to have the adverse reaction."

An what to think about Michael Adams-Conroy case? He was born with a gene deficiency to metabolize Prozac and that's why he died at the age of 9 years old. I'm sorry I'm not understanding.
I need help here.