I think a lot of what drives the creation of redundant open source tools is that the urge to address a matter of personal taste meets the urge to start a new project, so people create new things that are different in key ways from older ones, but not necessarily better, and not necessarily even different enough to justify the amount of work that goes into them.
In some ways it feels a lot easier to start a new project then to build off an existing one:
You don’t have to familiarize yourself with the old code, which may be in a language you don’t know or don’t like
You don’t have to deal with the existing maintainers, who may or may not be supportive of the changes you want to make
You don’t have to support use cases that don’t matter to you personally