>Isn't a government bond basically equivalent to inflation? That would mean you have a risk-free way to get "inflation" returns, with the caveat that you can't access the money for a period of time

It's not risk free, there is nothing that stops government from creating inflation so they can pay off the debt for in inflated dollars.

Today, central bank alone doesn't have power to make create money out of thin air. Government guaranteeing loans from banks to corporate players and projects is creating inflation. It's good for politicians as they can pay off their expensive mistakes in cheap money.