The fundamental.
1. Bitcoin is the no1 asset in the crypto world, all crypto assets depend on the Bitcoin price
2. Less Supply, try to compare it with the human population around the world
3. Huge Demand, the demand is increasing every day
4. Scarcity
5. Financial Freedom.
6. Decentralized
7. News, promoters, influencers and etc, will make Bitcoin easy to spread around the world
Finally FOMO; when some 10% or 20% of bitcoiners believe into $1M value for 1 bitcoin is going to happen then rest of people including people-yet-to-invest in crypto as well will get into FOMO which will be doing the rest of job. Moreover when we continuously talking about higher value then that will become as a target due to the same FOMO factor.