I'm guess impossible for dropped to $/btc. Why die? Bitcoin it's easy,fast,cheap and instand. People care for using bitcoin, and world now know it. 

it's not possible 650$ to 1$

I find this hard to believe too. Suppose a big dump would happen or people would lose faith I would expect the price to get to 200 max.
No whale or group of whales can't dump below that.

If the bitcoin drops that low i dont think the bticoin will survive allong time because when he hit the dollar each
There are allot of people who dont look after the bitcoins anymore and dont use them so it will be a catastrophe for the bitcoin.

Well for me, bitcoin will survive if the price drops to that price. As many people will take the advantage of buying more and will going to use their buying powers in able to give life bitcoin. And if many people are buying, then demand is increasing. And if demand is increasing for sure,
Price is going to increase too.

I would open up a few gambling sites on my browser, and watch the HR tabs being flooded with massive wagers, and of course, buy a few coins myself 

i think that would be a thing that i would most probably do to be honest, because the price would surely have a lot of chances to grow back again if it wont be banned by the government

i think i would sell all the coins at 10 dollars then or something like that because the price wouldnt grow back to 500 dollars in my opinion at least not so fast because people would be careful

I think miracle not going to happen twice so did with bitcoin if bitcoin just drop to 1$ even after halving which mean lower reward for miner,miners will go to another altcoin which have potential,and bitcoin will eventually die

buy as much as possible is the best choice, right? because i am sure it will rebound.