What will happened if every country started to use bitcoin. Is the current supply of bitcoin and blockchain capacity can handle every bitcoin user?
Thanks in advance.
I think that it would be really good because people who have invested in Bitcoin, us, would earn a lot of money because there would be so much demand and we would be able to supply. I don't know whether the blockchain would be able to handle all the users though. Only time can tell.
I think that you do wrong, assumpting that bitcoin is not used by all nations worldwide, it is pretty much used everywhere, but just by some units, not a whole communities. It is because not everybody knows about cryptocurrency, and even those who know, do not use BTC in every case, some people are just not interested, or they think this is some kind of a ponzi scheme.
And, about your speculations, it is rather a known fact, that blockchain would not handle so many users, we already have problems with a big traffic on network, probably SegWit would have fixed that, but many miners are against the SegWit, in favour of Bitcoin Unlimited.