1) States aren't valuing this above the closed source tracking solutions.
2) Some states aren't actively looking for a new solution (having one in place already).
Unfortunately both of these are hard problems to solve, and have almost nothing to do with technology (which it sounds like is your area of expertise).
> we assume that everyone knows distributed/federated systems are a good design goal
This sort of assumption is sadly not true, at least from what I've seen. I'm in the UK and we have the Government Digital Service. They're pretty much one of the best government IT services departments in the world, 18F was modelled on them and they train other governments to set up equivalent programmes.
GDS finds this hard! That's one centralised organisation, with wide veto power, and loads of deep tech/policy understanding that means they do value things like distributed/federated systems. Despite this, and while they've managed to overhaul the UK govt's IT services, they haven't substantially overhauled the open data scene. Even standards like Gov.UK Verify (distributed/federated identity verification) hasn't really caught on as they hoped after ~8 years.
If arguably the best placed organisation to roll this sort of thing out struggles to do it from inside a government, then I'm not sure that a tech-focused non-governmental organisation is going to manage this without very significant leverage.
That's what those existing tracking solutions probably do – they lobby. They'll spend money on lobbying (marketing) and sell contracts.
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I'm sorry this is such a negative answer, I'm all for open source interop protocols, but I guess I'm suggesting that you need to view it from a different perspective.
Assume that they don't care about it being open-source or federated. Assume that the closed source competitors are lobbying and doing all they can to legally bribe decision makers. Assume that even if you were actual government employees implementing this, that it would be an uphill battle.
Now, what can be done from those assumptions? Some things that come to mind are – grassroots organisation, getting everyone else onboard so that the incumbent tracking is essentially pointless? Maybe try for some legal challenge on the grounds of competition? Maybe hire someone who has sold the incumbent contracts to help you "sell" this in the tender process as if it were an existing solution.
I wish you all the best of luck, I'd love to see more open-source interop protocols for everything!