From my research, the strength of the cryptocurrencies lies on the mining power of the people.
it is actually the other way around. the mining power lies in the power and strength of the cryptocurrency.
for example a shitcoin with no strength will also have weak mining. if you increase its mining power it will never increase the strength of that cryptocurrency.
An economic stability and/or crisis of any nation doesn't determine the strength and the weakness of the cryptocurrencies.
i agree with this but the economic instability will definitely affect cryptocurrencies.
This is a great factor of important hence no country, no matter how strong can monopolize or manipulate cryptocurrencies,
monopolize and manipulate are two entirely different topics. also you can't talk about all cryptocurrencies at once.
as for manipulation, even individuals with enough power can manipulate anything even the biggest cryptocurrency. as it is evident from bitcoin.
but to monopolize a cryptocurrency you first have to centralize it. for example look at the centralized altcoins like XRP. the monopoly is very evident. there are other centralized coins that are not so obvious like ETH.
In the other hand, economically strong countries cannot aswell hijack cryptocurrencies. So, cryptocurrency is a currency for all.
this is again the same arguments about the level of centralization that the said cryptocurrency has. the more centralized they are the easier it would be to control them.