Modern monetary theory (MMT) is a (minority) branch of monetary theory the basic idea of which is that the government need not fund its expenses with taxes collected but through inflation, which is possible because it controls the money supply through the central bank. That is its most important deviation from classical economics. According to modern monetary theory, it is necessary to collect taxes only to prevent the economy from being overheated. By controlling the money supply, the government's role is to stimulate the economy sufficiently to keep employment at a high level by putting enough tokens into everyone's hands to enable them to transact.
Now, I will not get into the whole debate into whether MMT is a viable model or not. But it is notable how maintaining consensus and running the infrastructure on a public blockchain are precisely like public expenses such as security and the justice system in a political economy. They're absolutely necessary and must be paid for somehow. In real world economies, they're mostly paid for through tax collection, which would correspond to transaction fees paid for blockchain transactions. But maintaining consensus and paying for it is for the most part actually done through inflation in the vast majority of blockchains. Bitcoin miners get paid in newly minted bitcoins and Hive witnesses get their rather large share of the total token inflation.
It is amusing that so many in the space are "sound money" advocates and opposed to money being "created from thin air" because public blockchains pay their block validators in precisely that manner. The only difference between cryptocurrencies and central banks is that the monetary policy of a cryptocurrency is decided in a decentralized manner as opposed to a centralized manner when it is the task of a central bank.