1) There will always be enough BTC, since you can add more zeros and someday buy an awesome new car for 0.0000000000001776 BTC.
I've always thought that looks messy and unworkable.
I think it should look something like this: 0.(~12)1776 btc
With the number in the brackets representing the amount of zeros.
Or just introduce names like cent to dollars and Satoshi to bitcoin. What's the problem with saying 1776 Satoshi? Definitively better than 0.00001776 bitcoin.
It's already being attempted right now with "bits" which are worth 100 satoshis. If/when the BTC price is $1 million, each bit would be worth $1 and each satoshi would be worth $0.01. The whole thing would work in the same way most of our national currencies work today since everything would be written with two decimal places.
No one really knows how much because of the amount of the users of bitcoin. Imagine the guy who throw away his hard drive with tons of BTC in it. Yes that's a real news.
There was a story during the last boom about someon looking threw a tip to find his old PC hard drive because he has 1000BTC on it!
Yup,
here's an article about it.
It really goes to show how careless some early adopters were with their bitcoins back when they were virtually worthless. It wouldn't surprise me if many of the coins which were mined throughout 2009, 2010, and early 2011 also met the same fate. Another guy from Norway bought $25 worth of coins at around the same time, forgot about it, noticed in 2013 that the price exploded in the meantime, and then used his mined coins to buy an apartment. Despite the fact that both guys were extreme early adopters, whether or not they were actually able to take advantage of their unique situation pretty much boiled down to sheer luck:
He's not the first to forget about a lot of very valuable bits. But in a happier ending, a Norwegian man named Kristoffer Koch remembered his 2009 stash of $25 worth of bitcoins in time and cashed them out when they had grown in value to about $848,000.
Link:
http://www.cnet.com/news/man-forgets-he-once-bought-25-of-bitcoins-now-worth-848k/