Having a core system be entirely dependent on a foreign entity seems silly when there is a very viable alternative (which also saves a lot on licensing). I say VIABLE not equivalent. Linux is a lot rougher, and the change management process will be brutal. Retooling an entire department/etc to use whatever Linux has instead of entra/intune for device management will also be complex/incomplete/a learning curve.

TLDR: any govt would be crazy not to at least trial it, and see if it works.