- extremely difficult for beginners to understand
- currently expensive, making it less appealing than before
- mining is unpractical now which makes the entire network less secure
- other coins/token coming along with better technology
- highest fees of any crypto - and growing
- corrupt community, full of scammers
- mentioned above, scammers take advantage of the fact Bitcoin transactions are non-reversible
- not truly anonymous, can be traced by government
This list is in no way complete. The fact is if Bitcoin were to be remade today it would be a lot better. Hopefully we see improvements going forward, otherwise something new and better will likely take it over at some point.