I want to share my thought Why BTC Will Be Destroyed By Itself:
Every day Lot of people ( all of the Worlds) mining BTC it mean every day/Week/Year More BTC will be Injected to the Netwrok and it mean BTC abundance Will be increased and than Price will go lower and lower until 1$ probably.
Example:
Gold, silver and platinum are rare, thats why they are Expensive, BUT If Gold abundance was the same as Iron than Gold never was Expensive
As mentioned previously, there will be a maximum of 21 million BTC available, that is the cap. (You can read the white paper which is not that long)
There are 7 billion people in the world and 'only' 21 million BTC available once it caps out. If there is worldwide adoption, 21 million is not that much. Plus, a certain percentage is lost forever due to a loss of private keys / drive failure accidents, etc...