For those thinking about this question. I would suggest reading some background on the people, movements, and intellectual ideas that helped to inspire the invention of bitcoin.
For example this quote:
"Some of us believe various forms of strong cryptography will cause the power of the state to decline, perhaps even collapse fairly abruptly. We believe the expansion into cyberspace, with secure communications, digital money, anonymity and pseudonymity, and other crypto-mediated interactions, will profoundly change the nature of economies and social interactions.
Governments will have a hard time collecting taxes, regulating the behavior of individuals and corporations (small ones at least), and generally coercing folks when it can't even tell what _continent_ folks are on!" Timothy C May.
https://www.activism.net/cypherpunk/crypto-anarchy.htmlhttps://en.wikipedia.org/wiki/Crypto-anarchismhttps://en.wikipedia.org/wiki/CypherpunkPart of the idea inside bitcoin's invention is specifically to reduce the power of the nation-state. The genesis block message makes that very clear.
The original poster is probably mis-informed about what most taxes fund, when you remove the fraction of government spending that is actually mostly redistribution in nature, and focus on true spending associated with "action", it mostly is not about make a "good country". Widespread adoption of private digital money would specifically help eliminate gov effectiveness in collecting income, payroll, and capital/investment type taxes but the other more "natural" taxes such as tariffs, property taxes, and tolls can still be obviously collected. Those more natural taxes are what tend to make a country a "good one", such as schools, parks, roads, infrastructure. The other modern un-natural taxes along combined with the symbiotic connection to fiat central bank issued currencies are what is used to wage war and create destruction and death.
So yes. If you think ruining a Country would be the fall of nation states, then yes Bitcoin can ruin a Country. If you think building a more peaceful and prosperous world with smaller less violent and dangerous nations, then no, bitcoin won't ruin a country, it will probably eventually make it better, its just to get to the other side, we might have a really bumpy ride. So buckle up.