I don't think it is possible for Bitcoin to loose all its value as many people believe in Bitcoin and they have invested their money in it. Bitcoin is only growing and gaining popularity everyday so we can only expect growth from it. Minor pumps and dumps may be possible.
very honestly everything is possible and bitcoin can lose all its value, but i think bitcoin is now becoming so strong that it is now becoming so much difficult to happen. we can see that bitcoin is now becoming more stronger and in fact people are making even more stronger because they are putting more trust on bitcoin.