It is great to see that governments are also funding open source, but I don't think it is sustainable and scalable because:

1) In every country, most politicians and citizens have no clue about the problem we are discussing here. Thus OSS won't have a meaningful share in the gov budget.

2) If an OSS-advanced country funds open source now (like Germany - kudos to them!), it might easily change later with a new administration (like the support of nuclear plants in Germany).

3) If a very stable OSS-advanced country perpetually support open source, that creates a freerider problem - nowadays it seems that German taxpayers are supporting OSS, but others do not and unlikely will.

Meanwhile, private funding is sustainable (endowment model) and scalable because of aligned incentives — people voluntarily join, not taxed.