In the pharmaceutical world founders and employees more often have large opportunity costs by starting or joining a new venture. They are usually in their 30s or 40s with huge student loans, mortgage and kids. They forgo high incomes if they join a start-up. The road to the market is much longer (often more than 10 years). Investment in machinery is also at a completely different level. Drug development usually entails million dollar investment in specialized equipment. Perhaps the most costly aspect of drug development is the regulatory obstacles, such as getting approvals.
In contrast, IT companies are cheap. Founders often have little formal education (Microsoft, Facebook, Skype) and the road to market is much shorter. IT start-ups expect customers (or at least users) in a matter of weeks or months. Many IT companies can get to proof of concept with almost no investment in equipment. The founders simply bring their laptops on board). Regulatory concerns, if any, can usually be dealt with by one lawyer in a few days.
I cannot imagine anyone investing hundreds of millions of dollars in drug development over the course of 10 years without some assurance that competitors can't "steal" their idea. Usually that assurance is a patent or a trade secret. But keeping secrets over 10 years with employees coming and going - that's difficult.
tl;dr: Once you have an idea about, say a shopping cart in a web store, it can be implemented in a few man-weeks. Turning an idea about a new drug into a product often takes thousands of man-years. Whereas the institution of patents seems harmful in the world of software development, it may be necessary in the world drug development.