Bitcoin will not be able replace fiat for now because of several factors. Among them are unstable bitcoin exchange rates and international laws protecting bitcoins dont' yet.
Yes there are a lot of factors that bitcoin really can't be considered for replacing fiat. Even the price is getting higher and higher nowadays still that is not going to matter because in the end the government is the one that will be followed and law makers are coming from the. But let's see one day we will be having paperless transactions.
It's not about the price but on the adoption, fiat is adopted by all people in the world and even users of bitcoin is using it regularly, with the success of bitcoin will just make the transaction faster and will also increase the circulation of fiat, it's like fiat to bitcoin and then bitcoin back to fiat so at the end of the day all bitcoins will be converted to fiat in order to enjoy its value.
bitcoins value will be derived from how many people use it. when the user base of bitcoin becomes large enough, its conversion price to fiat currency will naturally stabilize and we wont see any crazy price swings like we did in the past
There is not a single chance of that
At least, not until instant, ping-time payment become available, and Bitcoin turns into a sort of "bad" money ("bad" money here refers to Gresham's Law obviously), though even in that case it is not given, either. Till then Bitcoin will remain mostly a speculative asset, and such assets can calm down only at zero level. There is simply no mechanism in place that would justify Bitcoin use for anything other than speculation on a large scale. And this is not going to change until and unless Bitcoin paradigm changes (e.g. due to introduction of payment channels with fast and free transactions)
Good point. Instantanous payment is definitely essential for price stability. Bitcoin and any sort of cryptocurrency would be unprecedented "bad" money as they do not have any intrinsic value to begin with.