The inventors had the "expectation" that Lucent would license their patent, but it doesn't say that they had an agreement to that effect, or that Lucent was bound in any way by existing IP law to do so. If Lucent was not required by law to do so, then it would be careless, if not irresponsible, to pay unnecessarily to license a patent.
The article is also vague about the contractural relationship between Lucent and the inventors. If you develop a product under contract, then that contract has to spell out very specifically who owns what rights to the product. It sounds as though the inventors left too many gray areas in their agreement, although that could just be the lack of detail in the article.
These guys sound like good inventors, but bad businessmen. And they had their lunch eaten by good businessmen. That's how it goes.