I would imagine that the cost of mining and running the blockchain is far less than the cost of the current banking system and financial industry.
per one transaction?
much more!
well the nextwork can handle 150 TX sec, with some downside... based on the last stress test, we are still far away form visa and company but the difference in power should be the same at the end
Yes, it really is unbreakable, with various caveats.
At the point of bitcoin exchange, there is vulnerability with bogus wallets and nefarious schemers...see Mt Gox fiasco.
Otherwise the system is sound, secure, decentralized, and pseudo-anonymous.
Well, it's certainly forkable. And this leads to problems with it being accepted more widely. The recent fork wasn't that bad (a 5 hour confirmation time is still great compared to credit cards), but you could imagine a situation where 51% adopt new specs but a 49% blockchain goes on for a long time, wreaking havoc among merchants and customers.
the miners are both the strengths and weaknesses of bitcoin
but you can always restart from zero if soemthing bad happened, cryptocoin will never die no matter what