I do not know who will destroy bitcoin, now the excessive mining monopoly, the cessation of the global internet (maybe).

One country cannot destroy Bitcoin. I think if all the government in each every countries we have here on Earth decided to stop trading/using Bitcoin, that's the end of our happy days.

Bitcoin can only destroy the loss of interest from users, but for this there must be a substitute by which people will start making money and hope for a brighter future.

It's almost impossible!
Maybe when it will totally banned?

Bitcoin cannot be destroyed unleass people don't use anymore. I don't think it can happen in near future.

Nobody can do it except Bitcoin will not be used anymore in the future. As all of you know, China is the country has biggest effect to Bitcoin all over the world but when China government banned Bitcoin and closed a lot of exchanges in thier country but it only affected to Bitcoin in few days and everything went fine right after that. But I think if the interney all over the world is not available anymore,  Bitcoin will die for sure.

Who knows soon or long enough some whales that stocked up so much BTCs that they could influence the market heavily, making small investors like us losing hope and leave the market.

An organized network of nations that banned BTC would kill BTC too if necessary, this only would be done if BTC was heavily changing how currency works soon if we look at it pessimistically.

0 is unlikely, but it is still possible to hit it back to the early days <$500-$1000, but if look at the bigger picture, Strong ALTs would quickly replace if such happens with a better and more advanced blockchain technology 

Maybe the one who can destroy the bitcoin is the government, if they think that it has no good result to the society especially when using this to illegal doing. Additionally, our economy was controlled by the government with taxes, if they don't have any partition maybe it will ban also because the currency of the country are affected. Just like in some countries that bitcoin was already ban because of competition in the currency, they hold a demand currency and bitcoin was the one who affect to their currency.

I think no one can destroy bitcoin because it's decentralized and no one can control it. It own its power only from people demand.

Bitcoin has the potential to become useful but powerful? Not likely and it sure isn’t useful yet.   95 percent of the services I buy and sell are not available with bitcoin.  I most cases I can’t use bitcoin to buy stock, bonds, a car, food, electricity, tires on and on and on.  It must become pervasive for it to really become useful.   I have hope this can happen but there is a long way to go. 

To use my possible bitcoin profits, I must got through an exchange and governments can shut them down in a second.  If that happens its only blackmarket central, nothing else.

As for who or what can take bitcoin out, at this point in time the US government can stop this thing dead in it’s tracks.  Make bitcoin transactions illegal and all it’s good for is use in the blackmarket.  That will still be big but nothing compared to what it could be.