An excerpt from a new article by Professor Karen Deak:
Why monetize a patent portfolio?
In short, companies exist to make money, and patents are a tool in the toolkit of revenue generation. Usually, sales of patented products are used to recoup the costs of the R&D that went into developing that product, and/or to fund a new round of R&D for the next innovative product.
A company's patent portfolio might additionally be looked at as a source of "free" revenue for the company. Most companies have patented technologies which they are not themselves exploiting; those patents and the underlying technologies may be attractive to another company which could make and sell (and therefore generate revenue) products using those technologies.
Read the entire article.