My top 3 would be:

Complacency: Satisfied with status quo, not looking for a change Laziness: Whether or not complacent, too lazy to study something new Distrust: Especially if confusing bitcoin with "crypto" which legitimately has tons of fraud

Related to complacency and laziness is the lack of a compelling and immediate use case for normies

Another reason could be fear. Media often tries to scare people away from it. Especially with lack in education people would hear things from others on how they make many mistakes with it.