Non-exclusive patent license agreements are accepted by a patent holder if they are denied an exclusive patent license agreement or they do not want the pressures of exclusive patent licensing, which include minimum annual royalty agreements. Non-exclusive patent licensing holders do not have the exclusive rights to a patent as suggested by the term, non-exclusive.
In fact, a licensor can grant many different non-exclusive licenses to different parties and then grant an exclusive license to another party. Once an exclusive license is obtained, no more non-exclusive licenses will be granted for the same patent. Non-exclusive patent license agreements are basically not worth much one a patent has been granted an exclusive patent license agreement.
Non-exclusive patent license agreement holders do not have protection from the licensor in the event of a lawsuit. Non-exclusive patents do not come with any affirmative rights such as ownership that would stand up in a trial. The licensor who granted the non-exclusive license will not and does not have to provide any protection in patent infringement cases, patent abandonment or length of license arguments.
A non-exclusive patent license agreement could possibly offer protection similar to exclusive agreements but only if the agreement states that such protection will be offered which is highly unlikely.
Licensors offer multiple non-exclusive licenses to assure that the patent will be used to its full potential. If one person is the holder of a license and they do not follow through with the production and distribution of the patent, that patent has gone to waste.
The more non-exclusive patent licensing agreements granted, the more likely a patent is able to live up to its full potential and the intellectual property can be successfully commercialized.