Reasons why they will keep fighting is not about the prosperity of the people majorly but about power and authority to control people. This is why they prefer the centralized system in order to keep the people poor so that they can run to their feet for daily bread, seek shelter and wait for other provision.
And I think you are having wrong impression on government and it operates. The centralized nature of government is never an attempt to make anyone poor but rather to maintain orderliness. It won't be possible to enforce compliance if there's no central authority and life will not fair with lower classes since there's no authority to create a fair environment for all. Relating to bitcoin, government is not fighting bitcoin but they're not too comfortable with its decentralization because it doesn't align with their form of operation.
We all know that through Bitcoin, every one will be there own boss. No control or submission to any authority over your own belonging or money, the life threatening taxes will be done away with.
But as of now, no matter how popular Bitcoin becomes, it will keep facing the wrath of the angry government who need to keep people poor.
Mind you, if government wants to impoverish people, bitcoin will neither make them rich. Assuming it's globally accepted as means of payment, you can only spend what you have.
Are we now in support of Bitcoin just to evade paying taxes?