Comment by tsoukase

Drug discovery and development is hard, unique and non comparable in the engineering world. It has it's own properties, like "the pipeline", I-... phases and a mere 20-year long patent duration (counting from molecule discovery). Imagine if after 20 years of it's inception on the paper the car's price falls 5-fold and you have to develop a new machine.

The failure rate does not take into account the millions of molecules that are tested by various methods of protein folding or binding properties. The 90% remains stable with time because on one side an end product is more difficult to produce, on the other the technology of molecule discovery has improved in the same amount.