A couple of facts: Innovator pharmaceutical research companies (Pfizer, Merck, Schering) spend billions of dollars annually developing potential drugs. A very few of these may show enough potential to be patented. A patent lasts 20 years. It will take 5 to 15 years and hundreds of millions of dollars more PER DRUG to perform all the FDA required testing to bring that drug to market. Most of these formulations never make into, let alone past Phase 1 clinical trials (There are 4 escalating phases). That leaves the innovator companies with an average of 9-11 years to recoup their investments in this successful drug, as well as in the drug research that didn't result in success, before the drug becomes avalable for copy by generic companies. A generic drug company need only meet some pretty basic FDA requirements (bioequivalence studies) to bring their generic drug to market. The innovator company has already done (and paid for) the safety and efficacy testing.
As for Zyprexa, it is a single pill that needs to be taken only once a day, which can make all the difference in the treatment of patients with mental disorders, who are notoriously difficult to medicate.
Bottom line: yes, the big pharmaceutical companies are out to make a buck, no one claims they are a non-profit venture. Unfortunately, they develop and market a commodity that affects whether people live or die. It's easy to villify them under those circumstances.
BTW: viagra was initially developed as a heart medication (its a vasodilator) when its unexpected side-affects were discovered. Pfizer was quick to spot the pot of gold, but in the end, it’s the consumer who creates the demand.