When you think about it, the question of theft doesn't really have much to do with how the money are spent afterwards, so achievements and failures in that persepective are not the most important thing to look at.

Theft is a crime and for theft to be the case some predefined elements of the crime should be met/proven for the crime to be determined to have taken place. For theft to have taken place something that is rightfully yours should be taken from you unrightfully. Is that the case with taxes? Do you have sovereign rights on everything you have come to control as part of society and taking advantage of all the public goods society has provided you with? I'm not sure the answer should necessarily be a yes. So either elements of the crime are hard to prove, both that you have rightful ownership of all your assets and that the government does not have a right to tax you on them.

You mention centralized government becoming void. What do you think will or could replace it? Wouldn't that be another form of government and could it function without any form of taxation?

You mention steemit as an alternative, but it's a system that builds upon all kinds of structures supported by governments and society. If it wasn't for government and taxes, the internet wouldn't exists and steemit couldn't exists without the internet.