That is what the Rust people have been doing for years, they have rewritten sudo, coreutils and many many other common tools such as less, cp, grep, etc.
One of the biggest issues with Ada/SPARK is that it lacks libraries that can hugely speed up the development of such tools. Also, less people know it, there is less momentum, the Ada tooling is quite unique and people do not want to learn it and packaging Ada software is a huuuuge pain in the ass, so software written in Ada is a pain to get into the repos for people to use it without friction…
Though I also share your vision and goal, this was not criticism towards it.
Best regards,
Fer
EDIT: actually, the issues I explain for Ada also existed in other languages, such as Fortran. But that community got the memo, bonded over it and created a somewhat “extended standard library for fortran” and now everybody uses it and the community has joined into creating a “single source of truth” for those libs and their usage has become pretty common. GitHub - fortran-lang/stdlib: Fortran Standard Library