Sure there have been hits, but there have been a lot of failures too.
The problem with "government VC" is not the low hit rate--private VC has a low hit rate too.
The problem is also not that government funds get gamed--private VC gets gamed too. See WeWork for an absolutely enormous example.
The problem is really with the different cultural expectations for government vs private capital.
If a private VC firm loses 95% of their investments to failure and fraud, but has huge hits with the remaining 5%, well, that's just how VC works. The only thing that really matters is their net. If they end up with a big return, they are geniuses.
But if the government loses 95% of their investments, that's a ton of wasted taxpayer money. That's a lot of fodder for press, politicians, and activists to make hay out of. And if the remaining 5% are hits, well, the government does not exist to turn a profit. So the credit does not work out the same, even if the hit rate is similar.