... is the system working as intended, because the policy rationale behind issuing lots of government bonds is precisely to make investors seek higher risks.
When downturns (like 2008) happen, this is investors fleeing to safe, money-like assets and and so wonks recommend that governments flood the markets with bonds, printed money, whatever to make that unprofitable.
The problem is with trying to fix the economy with policy levers. You can force people towards riskier investments (especially if they can be disguised as safe ones). But investment that is actually productive on average requires conditions where people on the ground can actually build useful stuff at a profit.
But that's an anathema to macro-economists (who want to advise on how use those levers) and also to politicians (who want to be seen to be "doing something").