Why?
one example: https://docs.moodle.org/22/en/Administration_via_command_lin...
?
PHP enforces memory limits out of the box by default. What languages have execution limits on CLI?
There are plenty of companies that rely on PHP that also have to work with CLI. I believe they are better informed when it comes to making decisions between handling CLI via an entirely different language and sticking to PHP.
Perhaps Peachpie, when it reaches production quality, will also help with that, as then calling .NET (and maybe, through that, WinRT) APIs from PHP code will be made easier.