Bubble
What is it?
A bubble is when there is so much hype over a certain thing that investors start evaluating that thing at overly high prices. The increasing price causes people to experience something called "fear of missing out". As a result, people buy and prices are fueled to soaring heights. Eventually reality hits home and a lot of people end up losing money once prices come crashing down.
Is Bitcoin a Bubble?
Maybe. We have yet to see whether bitcoin becomes a huge success or a massive failure. If it fails then it was a bubble. If it succeeds then it wasn't. So far I'm feeling pretty optimistic. There definitely is a lot of hype in the Bitcoin space, but the future will be the ultimate answer for whether that hype is warranted.
Example of a Bubble
The Dotcom Bubble[/center]
There can be more than one bubble in the same asset at different times. So saying that above is not really accurate as to what a bubble is or how it works.
Bitcoin went from $900 to $19,700 through 2017. That's a 2,000% increase. If it drops to $2,000 that would be an 90% drop. If bitcoin were to then rise again over time to $50,000 then according to your definition there will have been no bubble.
But, a 90% drop would definitely constitute a bubble. A bubble does not need to wipe out an asset, it just needs to be a point from which prices crash. And 90% would definitely be considered a crash by anyone's standards.
You gave the dotcom as an example of a bubble. Amazon and Facebook were part of that, as were other tech companies which have grown massively since they crashed. But they
were in a bubble but still survived.
So you see, you can have bubbles without obliterating the asset, which may then go on to greater heights in their value.