I love Linux but I've seen so many of these efforts fail. I did a move where we moved an entire election system onto centos. the move was a quarter billion dollars for them, but a couple years later they came back needing us to move to Redhat... then back to windows eventually.
the reason is governments are never willing to figure things out for themselves. if there's any error at all that happens that might make some gov officials look bad, they need a support line to call immediately and threaten breaking contracts. maybe these guys are fuckin with Canonical but Linux support is so shit from my experience.
as much as I hate Microsoft, you can pay them enough and they'll elevate your tickets to engineers who actually can do something and fix your shit. THAT is what governments actually want. somebody to sue or blame when their tech hits the fan.