This is the key argument for people promoting Bitcoin: Look how where we were a few months ago and look where we are now. It is only going faster - you should join.
This means that these people have jumped out of an airplane with no parachute.
They are now halfway down and are telling their friends: Look how well this is working, and it is going faster and faster.
When you tell the people they are going to crash-land, they just tell you it is FUD and that in their experience things have been going great since they jumped out of the airplane.
For me BTC it is not a pyramid. It is main currency of new currency type that will be used in the nearest future. Yeah, at present we see a lot of speculations and it is normal. I suppose all people remember events with gold 150 years ago..