They are fundamentally different - my language server is implemented in PHP so it can build on existing PHP parsers and PHP devs can contribute to it. Intelephense is written in TypeScript. They are two different approaches and both can coexist.
You can bump that date (and your experience), by making a pull request which I will happily review ;)
And I have to say that I've had better experiences with the latter. Also "last commit: 14.11.2018" on IntelliSense doesn't sound that great.