if all the governments of all the world joint hands together to banned bitcoins ,then only would bitcoin can come to an end.otherwise it is not gonna happen no where soon. because of its decentralization and no technology could beat because it is the first of its kind
That wouldn't be an end but it will certainly hit hard
The prices would likely go down dramatically if they would mean anything at all since most if not all exchanges will be closed down or denied access to (by the Greater World Firewall). Internet seems to be the weakest link where governments will likely hit first. Indeed, there is DarkWeb and things like Tor, but how many users would be using them? In other words, we would quick get back to the 10k bitcoins for a pizza times. Obviously, this is a doom and gloom scenario, and the longer Bitcoin exists the lesser are the chances for it to come true, but we still shouldn't write it off completely
That seems to be demonstrably not true in many/most instances. Normally criminalization of a desired thing increases it's value, and the more effective the enforcement, the higher the value goes.
You may argue that BTC would no longer be 'a desired thing' if Big Brother hassled users of it. I don't believe this is true at all, though it absolutely would change the makeup of the userbase significantly. Mostly it would shift it to the high-end criminal enterprise space, but this class is by no means small or weak. Such shift would be a direct consequence of government policy and no fault of Bitcoin
And I in advance agree with the examples you are likely going to bring forward proving the cases where the forbidden fruit is the sweetest. But these cases are obviously not applicable to Bitcoin. How come? Because Bitcoin has no value of its own. Right now its value comes from its use as an excellent vehicle for speculation and profiteering. But if it gets universally banned there will be no longer such use, and its utility will return to where it had been when Bitcoin was primarily used as a means of payment in the DarkWeb. How high it will cost in dollars would remain to be seen, but in any case you can safely forget about the first two digits in its price tag as of today