I think "decentralization of decision making" is a result, not a cause. I love it.
In geopolitical way of thinking, a state is always competing with other states. Not because we are bad people, but for the simple fact that states that can hold their own are likely to survive. Certain type of political "evolution".
To succeed in that competition you need armed forces. For that, you need manpower, equipment and supplies. All can be bought with money. So successful taxation is essential for any nation.
When traders and banks started to amass wealth at end of medieval period, any state that could tap into that flux of money had upper hand. But taxing individuals or sales actions or anything like that is more difficult than taxing nobles based on the land they hold. It helps a lot if those people have some sort of motivation to pay taxes. Concept of nation state provides such patriotic feelings. Now you are paying taxes for your people, not your feudal lord. Accounting and bureaucracy in general are also key elements.
French revolution established democracy and right after that the French levee en masse could defend the country against very big and powerful nations. Despite the facts that the french were short of money, had few trained troops and only little time. It showed that you could compensate with motivated and numerous troops. Imagine if you had democracy and money? This happened in the period where rifle had become more important in the battlefield than trained cavalry.
Possible scenarios? I think cryprocurrency will put traditional taxation in a binge. Governments need to tax what they can control, income and sales are going to be difficult. Taxation of energy seems easiest. Both persons and companies need energy. And it has some legitimacy with environmental concerns. Another big one is going to be information, it's difficult to lay cables without government knowing about it.
National identities don't seem to be important to people anymore. Conscription seems to become unneeded as well as unpopular. Bureaucracy is not going anywhere.
Political power seems to be shifting towards military-industrial big players. I don't think we will see feudalism. But maybe a modern version of powerful families of Venetian Republic. This time more with company allegiance than family ties.
Was that more understandable?
https://en.wikipedia.org/wiki/Lev%C3%A9e_en_masse
EDIT: I just would like to add that technological progress seems inevitable. But speed of technological development seems often biased. It's likely that current power structures pour R/D money on technologies that keep them in power. And it's completely possible that some unforeseen technology emerges and changes the picture totally.
I like Swedish arms production for this reason. For example they develop new anti-tank missiles to keep infantry relevant in the battlefield. Which in a way promotes democracy.