Without a community, an open source code repository is text files you can use to run or compile an application. An open source project needs maintainers, active contributors, a roadmap, etc. Github is full of very popular open source projects that have been completely abandoned, and forks of those projects that are also abandoned. An open source project having maintainers after a company has abandoned it is not the default. Sometimes it happens because the company nurtured an open source community before abandoning it, sometimes it happens because the project is crucial enough it scratches enough itches to attract volunteers. Sometimes it happens out of spite. But those are exceptions, not the rule.