Will someone make some sort of software for it?
They probably already have, sorta.
But, for taxing specifically?
I don't think that would work very well.
In order to tax bitcoin, you would have to force transactions to include transfers of bitcoin to the decentralized government.
Afaict, this would require either changing how bitcoin works specifically to accommodate this, or using some sort of threat to get people to pay the taxes.
Bitcoiners probably wouldn't be fond of either idea.
And the second idea would, uh, require some sort of force outside of computers, which would probably be prevented by the existing state, and even if it did "work" it probably wouldn't be decentralized.
Buffoon isn't really fully anonymous, but it is anonymous enough that taxing it would be infeasible I think?
Some other cryptocurrency could be created which has taxation built in, and a voting system which determines the amount of taxes etc., but I don't think adding it on to bitcoin as an external thing is feasible, at least not without using an already existing state.