In open source software/projects why do people release there codes with a permissive license instead of a copyleft license? I mean, the original author will not get back much (if anything at all) if they are releasing their code with a permissive license (like MIT) instead of a copyleft license (like GPL). At least copyleft prohibits the source code to be used in closed source proprietary software in the following way:
Permissive licenses don't prohibit this. So the author using a permissive license seems to be on the losing side. Yet, permissive licenses like the MIT license are the most used software licenses in the world for FOSS. Why is that the case? Because of altruism or something else?