They literally owe you nothing. They can walk away tomorrow, sell their github account, introduce breaking changes, add bugs, die, add crypto links, whatever.

>if they do not like those, they should hand off the project to a quoarum of >responsible maintainers and demote themselves to just a contributor.

The most responsible thing to do is to release it under an OSS license and let whoever, yes - including you, fork and maintain their own copy if it's that important.